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"
54 /* Types used by the record_gcc_switches() target function. */
57 SWITCH_TYPE_PASSED, /* A switch passed on the command line. */
58 SWITCH_TYPE_ENABLED, /* An option that is currently enabled. */
59 SWITCH_TYPE_DESCRIPTIVE, /* Descriptive text, not a switch or option. */
60 SWITCH_TYPE_LINE_START, /* Please emit any necessary text at the start of a line. */
61 SWITCH_TYPE_LINE_END /* Please emit a line terminator. */
65 typedef int (* print_switch_fn_type) (print_switch_type, const char *);
67 /* An example implementation for ELF targets. Defined in varasm.c */
68 extern int elf_record_gcc_switches (print_switch_type type, const char *);
73 /* The struct used by the secondary_reload target hook. */
74 typedef struct secondary_reload_info
76 /* icode is actually an enum insn_code, but we don't want to force every
77 file that includes target.h to include optabs.h . */
79 int extra_cost; /* Cost for using (a) scratch register(s) to be taken
80 into account by copy_cost. */
81 /* The next two members are for the use of the backward
82 compatibility hook. */
83 struct secondary_reload_info *prev_sri;
84 int t_icode; /* Actually an enum insn_code - see above. */
85 } secondary_reload_info;
87 /* This is defined in sched-int.h . */
92 /* Functions that output assembler for the target. */
95 /* Opening and closing parentheses for asm expression grouping. */
96 const char *open_paren, *close_paren;
98 /* Assembler instructions for creating various kinds of integer object. */
106 } aligned_op, unaligned_op;
108 /* Try to output the assembler code for an integer object whose
109 value is given by X. SIZE is the size of the object in bytes and
110 ALIGNED_P indicates whether it is aligned. Return true if
111 successful. Only handles cases for which BYTE_OP, ALIGNED_OP
112 and UNALIGNED_OP are NULL. */
113 bool (* integer) (rtx x, unsigned int size, int aligned_p);
115 /* Output code that will globalize a label. */
116 void (* globalize_label) (FILE *, const char *);
118 /* Output code that will globalize a declaration. */
119 void (* globalize_decl_name) (FILE *, tree);
121 /* Output code that will emit a label for unwind info, if this
122 target requires such labels. Second argument is the decl the
123 unwind info is associated with, third is a boolean: true if
124 this is for exception handling, fourth is a boolean: true if
125 this is only a placeholder for an omitted FDE. */
126 void (* unwind_label) (FILE *, tree, int, int);
128 /* Output code that will emit a label to divide up the exception
130 void (* except_table_label) (FILE *);
132 /* Emit any directives required to unwind this instruction. */
133 void (* unwind_emit) (FILE *, rtx);
135 /* Output an internal label. */
136 void (* internal_label) (FILE *, const char *, unsigned long);
138 /* Emit a ttype table reference to a typeinfo object. */
139 bool (* ttype) (rtx);
141 /* Emit an assembler directive to set visibility for the symbol
142 associated with the tree decl. */
143 void (* visibility) (tree, int);
145 /* Output the assembler code for entry to a function. */
146 void (* function_prologue) (FILE *, HOST_WIDE_INT);
148 /* Output the assembler code for end of prologue. */
149 void (* function_end_prologue) (FILE *);
151 /* Output the assembler code for start of epilogue. */
152 void (* function_begin_epilogue) (FILE *);
154 /* Output the assembler code for function exit. */
155 void (* function_epilogue) (FILE *, HOST_WIDE_INT);
157 /* Initialize target-specific sections. */
158 void (* init_sections) (void);
160 /* Tell assembler to change to section NAME with attributes FLAGS.
161 If DECL is non-NULL, it is the VAR_DECL or FUNCTION_DECL with
162 which this section is associated. */
163 void (* named_section) (const char *name, unsigned int flags, tree decl);
165 /* Return a mask describing how relocations should be treated when
166 selecting sections. Bit 1 should be set if global relocations
167 should be placed in a read-write section; bit 0 should be set if
168 local relocations should be placed in a read-write section. */
169 int (*reloc_rw_mask) (void);
171 /* Return a section for EXP. It may be a DECL or a constant. RELOC
172 is nonzero if runtime relocations must be applied; bit 1 will be
173 set if the runtime relocations require non-local name resolution.
174 ALIGN is the required alignment of the data. */
175 section *(* select_section) (tree, int, unsigned HOST_WIDE_INT);
177 /* Return a section for X. MODE is X's mode and ALIGN is its
178 alignment in bits. */
179 section *(* select_rtx_section) (enum machine_mode, rtx,
180 unsigned HOST_WIDE_INT);
182 /* Select a unique section name for DECL. RELOC is the same as
183 for SELECT_SECTION. */
184 void (* unique_section) (tree, int);
186 /* Return the readonly data section associated with function DECL. */
187 section *(* function_rodata_section) (tree);
189 /* Output a constructor for a symbol with a given priority. */
190 void (* constructor) (rtx, int);
192 /* Output a destructor for a symbol with a given priority. */
193 void (* destructor) (rtx, int);
195 /* Output the assembler code for a thunk function. THUNK_DECL is the
196 declaration for the thunk function itself, FUNCTION is the decl for
197 the target function. DELTA is an immediate constant offset to be
198 added to THIS. If VCALL_OFFSET is nonzero, the word at
199 *(*this + vcall_offset) should be added to THIS. */
200 void (* output_mi_thunk) (FILE *file, tree thunk_decl,
201 HOST_WIDE_INT delta, HOST_WIDE_INT vcall_offset,
204 /* Determine whether output_mi_thunk would succeed. */
205 /* ??? Ideally, this hook would not exist, and success or failure
206 would be returned from output_mi_thunk directly. But there's
207 too much undo-able setup involved in invoking output_mi_thunk.
208 Could be fixed by making output_mi_thunk emit rtl instead of
209 text to the output file. */
210 bool (* can_output_mi_thunk) (tree thunk_decl, HOST_WIDE_INT delta,
211 HOST_WIDE_INT vcall_offset,
214 /* Output any boilerplate text needed at the beginning of a
216 void (*file_start) (void);
218 /* Output any boilerplate text needed at the end of a
220 void (*file_end) (void);
222 /* Output an assembler pseudo-op to declare a library function name
224 void (*external_libcall) (rtx);
226 /* Output an assembler directive to mark decl live. This instructs
227 linker to not dead code strip this symbol. */
228 void (*mark_decl_preserved) (const char *);
230 /* Output a record of the command line switches that have been passed. */
231 print_switch_fn_type record_gcc_switches;
232 /* The name of the section that the example ELF implementation of
233 record_gcc_switches will use to store the information. Target
234 specific versions of record_gcc_switches may or may not use
236 const char * record_gcc_switches_section;
238 /* Output the definition of a section anchor. */
239 void (*output_anchor) (rtx);
241 /* Output a DTP-relative reference to a TLS symbol. */
242 void (*output_dwarf_dtprel) (FILE *file, int size, rtx x);
246 /* Functions relating to instruction scheduling. */
249 /* Given the current cost, COST, of an insn, INSN, calculate and
250 return a new cost based on its relationship to DEP_INSN through
251 the dependence LINK. The default is to make no adjustment. */
252 int (* adjust_cost) (rtx insn, rtx link, rtx dep_insn, int cost);
254 /* Adjust the priority of an insn as you see fit. Returns the new
256 int (* adjust_priority) (rtx, int);
258 /* Function which returns the maximum number of insns that can be
259 scheduled in the same machine cycle. This must be constant
260 over an entire compilation. The default is 1. */
261 int (* issue_rate) (void);
263 /* Calculate how much this insn affects how many more insns we
264 can emit this cycle. Default is they all cost the same. */
265 int (* variable_issue) (FILE *, int, rtx, int);
267 /* Initialize machine-dependent scheduling code. */
268 void (* md_init) (FILE *, int, int);
270 /* Finalize machine-dependent scheduling code. */
271 void (* md_finish) (FILE *, int);
273 /* Initialize machine-dependent function while scheduling code. */
274 void (* md_init_global) (FILE *, int, int);
276 /* Finalize machine-dependent function wide scheduling code. */
277 void (* md_finish_global) (FILE *, int);
279 /* Reorder insns in a machine-dependent fashion, in two different
280 places. Default does nothing. */
281 int (* reorder) (FILE *, int, rtx *, int *, int);
282 int (* reorder2) (FILE *, int, rtx *, int *, int);
284 /* The following member value is a pointer to a function called
285 after evaluation forward dependencies of insns in chain given
286 by two parameter values (head and tail correspondingly). */
287 void (* dependencies_evaluation_hook) (rtx, rtx);
289 /* The values of the following four members are pointers to
290 functions used to simplify the automaton descriptions.
291 dfa_pre_cycle_insn and dfa_post_cycle_insn give functions
292 returning insns which are used to change the pipeline hazard
293 recognizer state when the new simulated processor cycle
294 correspondingly starts and finishes. The function defined by
295 init_dfa_pre_cycle_insn and init_dfa_post_cycle_insn are used
296 to initialize the corresponding insns. The default values of
297 the members result in not changing the automaton state when
298 the new simulated processor cycle correspondingly starts and
300 void (* init_dfa_pre_cycle_insn) (void);
301 rtx (* dfa_pre_cycle_insn) (void);
302 void (* init_dfa_post_cycle_insn) (void);
303 rtx (* dfa_post_cycle_insn) (void);
305 /* The following member value is a pointer to a function returning value
306 which defines how many insns in queue `ready' will we try for
307 multi-pass scheduling. If the member value is nonzero and the
308 function returns positive value, the DFA based scheduler will make
309 multi-pass scheduling for the first cycle. In other words, we will
310 try to choose ready insn which permits to start maximum number of
311 insns on the same cycle. */
312 int (* first_cycle_multipass_dfa_lookahead) (void);
314 /* The following member value is pointer to a function controlling
315 what insns from the ready insn queue will be considered for the
316 multipass insn scheduling. If the hook returns zero for insn
317 passed as the parameter, the insn will be not chosen to be
319 int (* first_cycle_multipass_dfa_lookahead_guard) (rtx);
321 /* The following member value is pointer to a function called by
322 the insn scheduler before issuing insn passed as the third
323 parameter on given cycle. If the hook returns nonzero, the
324 insn is not issued on given processors cycle. Instead of that,
325 the processor cycle is advanced. If the value passed through
326 the last parameter is zero, the insn ready queue is not sorted
327 on the new cycle start as usually. The first parameter passes
328 file for debugging output. The second one passes the scheduler
329 verbose level of the debugging output. The forth and the fifth
330 parameter values are correspondingly processor cycle on which
331 the previous insn has been issued and the current processor
333 int (* dfa_new_cycle) (FILE *, int, rtx, int, int, int *);
335 /* The following member value is a pointer to a function called by the
336 insn scheduler. It should return true if there exists a dependence
337 which is considered costly by the target, between the insn
338 DEP_PRO (&_DEP), and the insn DEP_CON (&_DEP). The first parameter is
339 the dep that represents the dependence between the two insns. The
340 second argument is the cost of the dependence as estimated by
341 the scheduler. The last argument is the distance in cycles
342 between the already scheduled insn (first parameter) and the
343 the second insn (second parameter). */
344 bool (* is_costly_dependence) (struct _dep *_dep, int, int);
346 /* The following member value is a pointer to a function called
347 by the insn scheduler. This hook is called to notify the backend
348 that new instructions were emitted. */
349 void (* h_i_d_extended) (void);
351 /* The following member value is a pointer to a function called
352 by the insn scheduler.
353 The first parameter is an instruction, the second parameter is the type
354 of the requested speculation, and the third parameter is a pointer to the
355 speculative pattern of the corresponding type (set if return value == 1).
357 -1, if there is no pattern, that will satisfy the requested speculation
359 0, if current pattern satisfies the requested speculation type,
360 1, if pattern of the instruction should be changed to the newly
362 int (* speculate_insn) (rtx, int, rtx *);
364 /* The following member value is a pointer to a function called
365 by the insn scheduler. It should return true if the check instruction
366 corresponding to the instruction passed as the parameter needs a
368 bool (* needs_block_p) (rtx);
370 /* The following member value is a pointer to a function called
371 by the insn scheduler. It should return a pattern for the check
373 The first parameter is a speculative instruction, the second parameter
374 is the label of the corresponding recovery block (or null, if it is a
375 simple check). If the mutation of the check is requested (e.g. from
376 ld.c to chk.a), the third parameter is true - in this case the first
377 parameter is the previous check. */
378 rtx (* gen_check) (rtx, rtx, bool);
380 /* The following member value is a pointer to a function controlling
381 what insns from the ready insn queue will be considered for the
382 multipass insn scheduling. If the hook returns zero for the insn
383 passed as the parameter, the insn will not be chosen to be
384 issued. This hook is used to discard speculative instructions,
385 that stand at the first position of the ready list. */
386 bool (* first_cycle_multipass_dfa_lookahead_guard_spec) (rtx);
388 /* The following member value is a pointer to a function that provides
389 information about the speculation capabilities of the target.
390 The parameter is a pointer to spec_info variable. */
391 void (* set_sched_flags) (struct spec_info_def *);
394 /* Functions relating to vectorization. */
397 /* The following member value is a pointer to a function called
398 by the vectorizer, and return the decl of the target builtin
400 tree (* builtin_mask_for_load) (void);
402 /* Returns a code for builtin that realizes vectorized version of
403 function, or NULL_TREE if not available. */
404 tree (* builtin_vectorized_function) (unsigned, tree, tree);
406 /* Returns a code for builtin that realizes vectorized version of
407 conversion, or NULL_TREE if not available. */
408 tree (* builtin_conversion) (unsigned, tree);
410 /* Target builtin that implements vector widening multiplication.
411 builtin_mul_widen_eve computes the element-by-element products
412 for the even elements, and builtin_mul_widen_odd computes the
413 element-by-element products for the odd elements. */
414 tree (* builtin_mul_widen_even) (tree);
415 tree (* builtin_mul_widen_odd) (tree);
417 /* Returns the cost to be added to the overheads involved with
418 executing the vectorized version of a loop. */
419 int (*builtin_vectorization_cost) (bool);
421 /* Return true if vector alignment is reachable (by peeling N
422 interations) for the given type. */
423 bool (* vector_alignment_reachable) (tree, bool);
426 /* The initial value of target_flags. */
427 int default_target_flags;
429 /* Handle target switch CODE (an OPT_* value). ARG is the argument
430 passed to the switch; it is NULL if no argument was. VALUE is the
431 value of ARG if CODE specifies a UInteger option, otherwise it is
432 1 if the positive form of the switch was used and 0 if the negative
433 form was. Return true if the switch was valid. */
434 bool (* handle_option) (size_t code, const char *arg, int value);
436 /* Display extra, target specific information in response to a
437 --target-help switch. */
438 void (* target_help) (void);
440 /* Return machine mode for filter value. */
441 enum machine_mode (* eh_return_filter_mode) (void);
443 /* Return machine mode for libgcc expanded cmp instructions. */
444 enum machine_mode (* libgcc_cmp_return_mode) (void);
446 /* Return machine mode for libgcc expanded shift instructions. */
447 enum machine_mode (* libgcc_shift_count_mode) (void);
449 /* Given two decls, merge their attributes and return the result. */
450 tree (* merge_decl_attributes) (tree, tree);
452 /* Given two types, merge their attributes and return the result. */
453 tree (* merge_type_attributes) (tree, tree);
455 /* Table of machine attributes and functions to handle them.
457 const struct attribute_spec *attribute_table;
459 /* Return zero if the attributes on TYPE1 and TYPE2 are incompatible,
460 one if they are compatible and two if they are nearly compatible
461 (which causes a warning to be generated). */
462 int (* comp_type_attributes) (tree type1, tree type2);
464 /* Assign default attributes to the newly defined TYPE. */
465 void (* set_default_type_attributes) (tree type);
467 /* Insert attributes on the newly created DECL. */
468 void (* insert_attributes) (tree decl, tree *attributes);
470 /* Return true if FNDECL (which has at least one machine attribute)
471 can be inlined despite its machine attributes, false otherwise. */
472 bool (* function_attribute_inlinable_p) (tree fndecl);
474 /* Return true if bitfields in RECORD_TYPE should follow the
475 Microsoft Visual C++ bitfield layout rules. */
476 bool (* ms_bitfield_layout_p) (tree record_type);
478 /* True if the target supports decimal floating point. */
479 bool (* decimal_float_supported_p) (void);
481 /* Return true if anonymous bitfields affect structure alignment. */
482 bool (* align_anon_bitfield) (void);
484 /* Return true if volatile bitfields should use the narrowest type possible.
485 Return false if they should use the container type. */
486 bool (* narrow_volatile_bitfield) (void);
488 /* Set up target-specific built-in functions. */
489 void (* init_builtins) (void);
491 /* Expand a target-specific builtin. */
492 rtx (* expand_builtin) (tree exp, rtx target, rtx subtarget,
493 enum machine_mode mode, int ignore);
495 /* Select a replacement for a target-specific builtin. This is done
496 *before* regular type checking, and so allows the target to implement
497 a crude form of function overloading. The result is a complete
498 expression that implements the operation. */
499 tree (*resolve_overloaded_builtin) (tree decl, tree params);
501 /* Fold a target-specific builtin. */
502 tree (* fold_builtin) (tree fndecl, tree arglist, bool ignore);
504 /* Returns a code for a target-specific builtin that implements
505 reciprocal of the function, or NULL_TREE if not available. */
506 tree (* builtin_reciprocal) (unsigned, bool, bool);
508 /* For a vendor-specific TYPE, return a pointer to a statically-allocated
509 string containing the C++ mangling for TYPE. In all other cases, return
511 const char * (* mangle_type) (tree type);
513 /* Make any adjustments to libfunc names needed for this target. */
514 void (* init_libfuncs) (void);
516 /* Given a decl, a section name, and whether the decl initializer
517 has relocs, choose attributes for the section. */
518 /* ??? Should be merged with SELECT_SECTION and UNIQUE_SECTION. */
519 unsigned int (* section_type_flags) (tree, const char *, int);
521 /* True if new jumps cannot be created, to replace existing ones or
522 not, at the current point in the compilation. */
523 bool (* cannot_modify_jumps_p) (void);
525 /* Return a register class for which branch target register
526 optimizations should be applied. */
527 int (* branch_target_register_class) (void);
529 /* Return true if branch target register optimizations should include
530 callee-saved registers that are not already live during the current
531 function. AFTER_PE_GEN is true if prologues and epilogues have
532 already been generated. */
533 bool (* branch_target_register_callee_saved) (bool after_pe_gen);
535 /* True if the constant X cannot be placed in the constant pool. */
536 bool (* cannot_force_const_mem) (rtx);
538 /* True if the insn X cannot be duplicated. */
539 bool (* cannot_copy_insn_p) (rtx);
541 /* True if X is considered to be commutative. */
542 bool (* commutative_p) (rtx, int);
544 /* Given an address RTX, undo the effects of LEGITIMIZE_ADDRESS. */
545 rtx (* delegitimize_address) (rtx);
547 /* True if the given constant can be put into an object_block. */
548 bool (* use_blocks_for_constant_p) (enum machine_mode, rtx);
550 /* The minimum and maximum byte offsets for anchored addresses. */
551 HOST_WIDE_INT min_anchor_offset;
552 HOST_WIDE_INT max_anchor_offset;
554 /* True if section anchors can be used to access the given symbol. */
555 bool (* use_anchors_for_symbol_p) (rtx);
557 /* True if it is OK to do sibling call optimization for the specified
558 call expression EXP. DECL will be the called function, or NULL if
559 this is an indirect call. */
560 bool (*function_ok_for_sibcall) (tree decl, tree exp);
562 /* True if EXP should be placed in a "small data" section. */
563 bool (* in_small_data_p) (tree);
565 /* True if EXP names an object for which name resolution must resolve
566 to the current module. */
567 bool (* binds_local_p) (tree);
569 /* Modify and return the identifier of a DECL's external name,
570 originally identified by ID, as required by the target,
571 (eg, append @nn to windows32 stdcall function names).
572 The default is to return ID without modification. */
573 tree (* mangle_decl_assembler_name) (tree decl, tree id);
575 /* Do something target-specific to record properties of the DECL into
576 the associated SYMBOL_REF. */
577 void (* encode_section_info) (tree, rtx, int);
579 /* Undo the effects of encode_section_info on the symbol string. */
580 const char * (* strip_name_encoding) (const char *);
582 /* If shift optabs for MODE are known to always truncate the shift count,
583 return the mask that they apply. Return 0 otherwise. */
584 unsigned HOST_WIDE_INT (* shift_truncation_mask) (enum machine_mode mode);
586 /* Return the number of divisions in the given MODE that should be present,
587 so that it is profitable to turn the division into a multiplication by
589 unsigned int (* min_divisions_for_recip_mul) (enum machine_mode mode);
591 /* If the representation of integral MODE is such that values are
592 always sign-extended to a wider mode MODE_REP then return
593 SIGN_EXTEND. Return UNKNOWN otherwise. */
594 /* Note that the return type ought to be RTX_CODE, but that's not
595 necessarily defined at this point. */
596 int (* mode_rep_extended) (enum machine_mode mode,
597 enum machine_mode mode_rep);
599 /* True if MODE is valid for a pointer in __attribute__((mode("MODE"))). */
600 bool (* valid_pointer_mode) (enum machine_mode mode);
602 /* True if MODE is valid for the target. By "valid", we mean able to
603 be manipulated in non-trivial ways. In particular, this means all
604 the arithmetic is supported. */
605 bool (* scalar_mode_supported_p) (enum machine_mode mode);
607 /* Similarly for vector modes. "Supported" here is less strict. At
608 least some operations are supported; need to check optabs or builtins
609 for further details. */
610 bool (* vector_mode_supported_p) (enum machine_mode mode);
612 /* True if a vector is opaque. */
613 bool (* vector_opaque_p) (tree);
615 /* Compute a (partial) cost for rtx X. Return true if the complete
616 cost has been computed, and false if subexpressions should be
617 scanned. In either case, *TOTAL contains the cost result. */
618 /* Note that CODE and OUTER_CODE ought to be RTX_CODE, but that's
619 not necessarily defined at this point. */
620 bool (* rtx_costs) (rtx x, int code, int outer_code, int *total);
622 /* Compute the cost of X, used as an address. Never called with
623 invalid addresses. */
624 int (* address_cost) (rtx x);
626 /* Return where to allocate pseudo for a given hard register initial
628 rtx (* allocate_initial_value) (rtx x);
630 /* Given a register, this hook should return a parallel of registers
631 to represent where to find the register pieces. Define this hook
632 if the register and its mode are represented in Dwarf in
633 non-contiguous locations, or if the register should be
634 represented in more than one register in Dwarf. Otherwise, this
635 hook should return NULL_RTX. */
636 rtx (* dwarf_register_span) (rtx);
638 /* If expand_builtin_init_dwarf_reg_sizes needs to fill in table
639 entries not corresponding directly to registers below
640 FIRST_PSEUDO_REGISTER, this hook should generate the necessary
641 code, given the address of the table. */
642 void (* init_dwarf_reg_sizes_extra) (tree);
644 /* Fetch the fixed register(s) which hold condition codes, for
645 targets where it makes sense to look for duplicate assignments to
646 the condition codes. This should return true if there is such a
647 register, false otherwise. The arguments should be set to the
648 fixed register numbers. Up to two condition code registers are
649 supported. If there is only one for this target, the int pointed
650 at by the second argument should be set to -1. */
651 bool (* fixed_condition_code_regs) (unsigned int *, unsigned int *);
653 /* If two condition code modes are compatible, return a condition
654 code mode which is compatible with both, such that a comparison
655 done in the returned mode will work for both of the original
656 modes. If the condition code modes are not compatible, return
658 enum machine_mode (* cc_modes_compatible) (enum machine_mode,
661 /* Do machine-dependent code transformations. Called just before
662 delayed-branch scheduling. */
663 void (* machine_dependent_reorg) (void);
665 /* Create the __builtin_va_list type. */
666 tree (* build_builtin_va_list) (void);
668 /* Gimplifies a VA_ARG_EXPR. */
669 tree (* gimplify_va_arg_expr) (tree valist, tree type, tree *pre_p,
672 /* Validity-checking routines for PCH files, target-specific.
673 get_pch_validity returns a pointer to the data to be stored,
674 and stores the size in its argument. pch_valid_p gets the same
675 information back and returns NULL if the PCH is valid,
676 or an error message if not.
678 void * (* get_pch_validity) (size_t *);
679 const char * (* pch_valid_p) (const void *, size_t);
681 /* If nonnull, this function checks whether a PCH file with the
682 given set of target flags can be used. It returns NULL if so,
683 otherwise it returns an error message. */
684 const char *(*check_pch_target_flags) (int);
686 /* True if the compiler should give an enum type only as many
687 bytes as it takes to represent the range of possible values of
689 bool (* default_short_enums) (void);
691 /* This target hook returns an rtx that is used to store the address
692 of the current frame into the built-in setjmp buffer. */
693 rtx (* builtin_setjmp_frame_value) (void);
695 /* This target hook should add STRING_CST trees for any hard regs
696 the port wishes to automatically clobber for an asm. */
697 tree (* md_asm_clobbers) (tree, tree, tree);
699 /* This target hook allows the backend to specify a calling convention
700 in the debug information. This function actually returns an
701 enum dwarf_calling_convention, but because of forward declarations
702 and not wanting to include dwarf2.h everywhere target.h is included
703 the function is being declared as an int. */
704 int (* dwarf_calling_convention) (tree);
706 /* This target hook allows the backend to emit frame-related insns that
707 contain UNSPECs or UNSPEC_VOLATILEs. The call frame debugging info
708 engine will invoke it on insns of the form
709 (set (reg) (unspec [...] UNSPEC_INDEX))
711 (set (reg) (unspec_volatile [...] UNSPECV_INDEX))
712 to let the backend emit the call frame instructions. */
713 void (* dwarf_handle_frame_unspec) (const char *, rtx, int);
715 /* Perform architecture specific checking of statements gimplified
716 from VA_ARG_EXPR. LHS is left hand side of MODIFY_EXPR, RHS
717 is right hand side. Returns true if the statements doesn't need
718 to be checked for va_list references. */
719 bool (* stdarg_optimize_hook) (struct stdarg_info *ai, tree lhs, tree rhs);
721 /* This target hook allows the operating system to override the DECL
722 that represents the external variable that contains the stack
723 protection guard variable. The type of this DECL is ptr_type_node. */
724 tree (* stack_protect_guard) (void);
726 /* This target hook allows the operating system to override the CALL_EXPR
727 that is invoked when a check vs the guard variable fails. */
728 tree (* stack_protect_fail) (void);
730 /* Returns NULL if target supports the insn within a doloop block,
731 otherwise it returns an error message. */
732 const char * (*invalid_within_doloop) (rtx);
734 /* DECL is a variable or function with __attribute__((dllimport))
735 specified. Use this hook if the target needs to add extra validation
736 checks to handle_dll_attribute (). */
737 bool (* valid_dllimport_attribute_p) (tree decl);
739 /* Functions relating to calls - argument passing, returns, etc. */
741 bool (*promote_function_args) (tree fntype);
742 bool (*promote_function_return) (tree fntype);
743 bool (*promote_prototypes) (tree fntype);
744 rtx (*struct_value_rtx) (tree fndecl, int incoming);
745 bool (*return_in_memory) (tree type, tree fndecl);
746 bool (*return_in_msb) (tree type);
748 /* Return true if a parameter must be passed by reference. TYPE may
749 be null if this is a libcall. CA may be null if this query is
750 from __builtin_va_arg. */
751 bool (*pass_by_reference) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
752 tree type, bool named_arg);
754 rtx (*expand_builtin_saveregs) (void);
755 /* Returns pretend_argument_size. */
756 void (*setup_incoming_varargs) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
757 tree type, int *pretend_arg_size,
759 bool (*strict_argument_naming) (CUMULATIVE_ARGS *ca);
760 /* Returns true if we should use
761 targetm.calls.setup_incoming_varargs() and/or
762 targetm.calls.strict_argument_naming(). */
763 bool (*pretend_outgoing_varargs_named) (CUMULATIVE_ARGS *ca);
765 /* Given a complex type T, return true if a parameter of type T
766 should be passed as two scalars. */
767 bool (* split_complex_arg) (tree type);
769 /* Return true if type T, mode MODE, may not be passed in registers,
770 but must be passed on the stack. */
771 /* ??? This predicate should be applied strictly after pass-by-reference.
772 Need audit to verify that this is the case. */
773 bool (* must_pass_in_stack) (enum machine_mode mode, tree t);
775 /* Return true if type TYPE, mode MODE, which is passed by reference,
776 should have the object copy generated by the callee rather than
777 the caller. It is never called for TYPE requiring constructors. */
778 bool (* callee_copies) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
779 tree type, bool named);
781 /* Return zero for arguments passed entirely on the stack or entirely
782 in registers. If passed in both, return the number of bytes passed
783 in registers; the balance is therefore passed on the stack. */
784 int (* arg_partial_bytes) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
785 tree type, bool named);
787 /* Return the diagnostic message string if function without a prototype
788 is not allowed for this 'val' argument; NULL otherwise. */
789 const char *(*invalid_arg_for_unprototyped_fn) (tree typelist,
790 tree funcdecl, tree val);
792 /* Return an rtx for the return value location of the function
793 specified by FN_DECL_OR_TYPE with a return type of RET_TYPE. */
794 rtx (*function_value) (tree ret_type, tree fn_decl_or_type,
797 /* Return an rtx for the argument pointer incoming to the
799 rtx (*internal_arg_pointer) (void);
802 /* Return the diagnostic message string if conversion from FROMTYPE
803 to TOTYPE is not allowed, NULL otherwise. */
804 const char *(*invalid_conversion) (tree fromtype, tree totype);
806 /* Return the diagnostic message string if the unary operation OP is
807 not permitted on TYPE, NULL otherwise. */
808 const char *(*invalid_unary_op) (int op, tree type);
810 /* Return the diagnostic message string if the binary operation OP
811 is not permitted on TYPE1 and TYPE2, NULL otherwise. */
812 const char *(*invalid_binary_op) (int op, tree type1, tree type2);
814 /* Return the class for a secondary reload, and fill in extra information. */
815 enum reg_class (*secondary_reload) (bool, rtx, enum reg_class,
817 struct secondary_reload_info *);
819 /* Functions specific to the C family of frontends. */
821 /* Return machine mode for non-standard suffix
822 or VOIDmode if non-standard suffixes are unsupported. */
823 enum machine_mode (*mode_for_suffix) (char);
826 /* Functions specific to the C++ frontend. */
828 /* Return the integer type used for guard variables. */
829 tree (*guard_type) (void);
830 /* Return true if only the low bit of the guard should be tested. */
831 bool (*guard_mask_bit) (void);
832 /* Returns the size of the array cookie for an array of type. */
833 tree (*get_cookie_size) (tree);
834 /* Returns true if the element size should be stored in the
836 bool (*cookie_has_size) (void);
837 /* Allows backends to perform additional processing when
838 deciding if a class should be exported or imported. */
839 int (*import_export_class) (tree, int);
840 /* Returns true if constructors and destructors return "this". */
841 bool (*cdtor_returns_this) (void);
842 /* Returns true if the key method for a class can be an inline
843 function, so long as it is not declared inline in the class
844 itself. Returning true is the behavior required by the Itanium
846 bool (*key_method_may_be_inline) (void);
847 /* DECL is a virtual table, virtual table table, typeinfo object,
848 or other similar implicit class data object that will be
849 emitted with external linkage in this translation unit. No ELF
850 visibility has been explicitly specified. If the target needs
851 to specify a visibility other than that of the containing class,
852 use this hook to set DECL_VISIBILITY and
853 DECL_VISIBILITY_SPECIFIED. */
854 void (*determine_class_data_visibility) (tree decl);
855 /* Returns true (the default) if virtual tables and other
856 similar implicit class data objects are always COMDAT if they
857 have external linkage. If this hook returns false, then
858 class data for classes whose virtual table will be emitted in
859 only one translation unit will not be COMDAT. */
860 bool (*class_data_always_comdat) (void);
861 /* Returns true (the default) if the RTTI for the basic types,
862 which is always defined in the C++ runtime, should be COMDAT;
863 false if it should not be COMDAT. */
864 bool (*library_rtti_comdat) (void);
865 /* Returns true if __aeabi_atexit should be used to register static
867 bool (*use_aeabi_atexit) (void);
868 /* Returns true if target may use atexit in the same manner as
869 __cxa_atexit to register static destructors. */
870 bool (*use_atexit_for_cxa_atexit) (void);
871 /* TYPE is a C++ class (i.e., RECORD_TYPE or UNION_TYPE) that
872 has just been defined. Use this hook to make adjustments to the
873 class (eg, tweak visibility or perform any other required
874 target modifications). */
875 void (*adjust_class_at_definition) (tree type);
878 /* For targets that need to mark extra registers as live on entry to
879 the function, they should define this target hook and set their
880 bits in the bitmap passed in. */
881 void (*live_on_entry) (bitmap);
883 /* True if unwinding tables should be generated by default. */
884 bool unwind_tables_default;
886 /* Leave the boolean fields at the end. */
888 /* True if arbitrary sections are supported. */
889 bool have_named_sections;
891 /* True if we can create zeroed data by switching to a BSS section
892 and then using ASM_OUTPUT_SKIP to allocate the space. */
893 bool have_switchable_bss_sections;
895 /* True if "native" constructors and destructors are supported,
896 false if we're using collect2 for the job. */
897 bool have_ctors_dtors;
899 /* True if thread-local storage is supported. */
902 /* True if a small readonly data section is supported. */
903 bool have_srodata_section;
905 /* True if EH frame info sections should be zero-terminated. */
906 bool terminate_dw2_eh_frame_info;
908 /* True if #NO_APP should be emitted at the beginning of
910 bool file_start_app_off;
912 /* True if output_file_directive should be called for main_input_filename
913 at the beginning of assembly output. */
914 bool file_start_file_directive;
916 /* True if #pragma redefine_extname is to be supported. */
917 bool handle_pragma_redefine_extname;
919 /* True if #pragma extern_prefix is to be supported. */
920 bool handle_pragma_extern_prefix;
922 /* True if the target is allowed to reorder memory accesses unless
923 synchronization is explicitly requested. */
924 bool relaxed_ordering;
926 /* Returns true if we should generate exception tables for use with the
927 ARM EABI. The effects the encoding of function exception specifications.
929 bool arm_eabi_unwinder;
931 /* Leave the boolean fields at the end. */
934 extern struct gcc_target targetm;
936 struct gcc_targetcm {
937 /* Handle target switch CODE (an OPT_* value). ARG is the argument
938 passed to the switch; it is NULL if no argument was. VALUE is the
939 value of ARG if CODE specifies a UInteger option, otherwise it is
940 1 if the positive form of the switch was used and 0 if the negative
941 form was. Return true if the switch was valid. */
942 bool (*handle_c_option) (size_t code, const char *arg, int value);
945 /* Each target can provide their own. */
946 extern struct gcc_targetcm targetcm;
948 #endif /* GCC_TARGET_H */
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