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 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 . */
93 /* Functions that output assembler for the target. */
96 /* Opening and closing parentheses for asm expression grouping. */
97 const char *open_paren, *close_paren;
99 /* Assembler instructions for creating various kinds of integer object. */
107 } aligned_op, unaligned_op;
109 /* Try to output the assembler code for an integer object whose
110 value is given by X. SIZE is the size of the object in bytes and
111 ALIGNED_P indicates whether it is aligned. Return true if
112 successful. Only handles cases for which BYTE_OP, ALIGNED_OP
113 and UNALIGNED_OP are NULL. */
114 bool (* integer) (rtx x, unsigned int size, int aligned_p);
116 /* Output code that will globalize a label. */
117 void (* globalize_label) (FILE *, const char *);
119 /* Output code that will globalize a declaration. */
120 void (* globalize_decl_name) (FILE *, tree);
122 /* Output code that will emit a label for unwind info, if this
123 target requires such labels. Second argument is the decl the
124 unwind info is associated with, third is a boolean: true if
125 this is for exception handling, fourth is a boolean: true if
126 this is only a placeholder for an omitted FDE. */
127 void (* unwind_label) (FILE *, tree, int, int);
129 /* Output code that will emit a label to divide up the exception
131 void (* except_table_label) (FILE *);
133 /* Emit any directives required to unwind this instruction. */
134 void (* unwind_emit) (FILE *, rtx);
136 /* Output an internal label. */
137 void (* internal_label) (FILE *, const char *, unsigned long);
139 /* Emit a ttype table reference to a typeinfo object. */
140 bool (* ttype) (rtx);
142 /* Emit an assembler directive to set visibility for the symbol
143 associated with the tree decl. */
144 void (* visibility) (tree, int);
146 /* Output the assembler code for entry to a function. */
147 void (* function_prologue) (FILE *, HOST_WIDE_INT);
149 /* Output the assembler code for end of prologue. */
150 void (* function_end_prologue) (FILE *);
152 /* Output the assembler code for start of epilogue. */
153 void (* function_begin_epilogue) (FILE *);
155 /* Output the assembler code for function exit. */
156 void (* function_epilogue) (FILE *, HOST_WIDE_INT);
158 /* Initialize target-specific sections. */
159 void (* init_sections) (void);
161 /* Tell assembler to change to section NAME with attributes FLAGS.
162 If DECL is non-NULL, it is the VAR_DECL or FUNCTION_DECL with
163 which this section is associated. */
164 void (* named_section) (const char *name, unsigned int flags, tree decl);
166 /* Return a mask describing how relocations should be treated when
167 selecting sections. Bit 1 should be set if global relocations
168 should be placed in a read-write section; bit 0 should be set if
169 local relocations should be placed in a read-write section. */
170 int (*reloc_rw_mask) (void);
172 /* Return a section for EXP. It may be a DECL or a constant. RELOC
173 is nonzero if runtime relocations must be applied; bit 1 will be
174 set if the runtime relocations require non-local name resolution.
175 ALIGN is the required alignment of the data. */
176 section *(* select_section) (tree, int, unsigned HOST_WIDE_INT);
178 /* Return a section for X. MODE is X's mode and ALIGN is its
179 alignment in bits. */
180 section *(* select_rtx_section) (enum machine_mode, rtx,
181 unsigned HOST_WIDE_INT);
183 /* Select a unique section name for DECL. RELOC is the same as
184 for SELECT_SECTION. */
185 void (* unique_section) (tree, int);
187 /* Return the readonly data section associated with function DECL. */
188 section *(* function_rodata_section) (tree);
190 /* Output a constructor for a symbol with a given priority. */
191 void (* constructor) (rtx, int);
193 /* Output a destructor for a symbol with a given priority. */
194 void (* destructor) (rtx, int);
196 /* Output the assembler code for a thunk function. THUNK_DECL is the
197 declaration for the thunk function itself, FUNCTION is the decl for
198 the target function. DELTA is an immediate constant offset to be
199 added to THIS. If VCALL_OFFSET is nonzero, the word at
200 *(*this + vcall_offset) should be added to THIS. */
201 void (* output_mi_thunk) (FILE *file, tree thunk_decl,
202 HOST_WIDE_INT delta, HOST_WIDE_INT vcall_offset,
205 /* Determine whether output_mi_thunk would succeed. */
206 /* ??? Ideally, this hook would not exist, and success or failure
207 would be returned from output_mi_thunk directly. But there's
208 too much undo-able setup involved in invoking output_mi_thunk.
209 Could be fixed by making output_mi_thunk emit rtl instead of
210 text to the output file. */
211 bool (* can_output_mi_thunk) (const_tree thunk_decl, HOST_WIDE_INT delta,
212 HOST_WIDE_INT vcall_offset,
213 const_tree function_decl);
215 /* Output any boilerplate text needed at the beginning of a
217 void (*file_start) (void);
219 /* Output any boilerplate text needed at the end of a
221 void (*file_end) (void);
223 /* Output an assembler pseudo-op to declare a library function name
225 void (*external_libcall) (rtx);
227 /* Output an assembler directive to mark decl live. This instructs
228 linker to not dead code strip this symbol. */
229 void (*mark_decl_preserved) (const char *);
231 /* Output a record of the command line switches that have been passed. */
232 print_switch_fn_type record_gcc_switches;
233 /* The name of the section that the example ELF implementation of
234 record_gcc_switches will use to store the information. Target
235 specific versions of record_gcc_switches may or may not use
237 const char * record_gcc_switches_section;
239 /* Output the definition of a section anchor. */
240 void (*output_anchor) (rtx);
242 /* Output a DTP-relative reference to a TLS symbol. */
243 void (*output_dwarf_dtprel) (FILE *file, int size, rtx x);
247 /* Functions relating to instruction scheduling. */
250 /* Given the current cost, COST, of an insn, INSN, calculate and
251 return a new cost based on its relationship to DEP_INSN through
252 the dependence LINK. The default is to make no adjustment. */
253 int (* adjust_cost) (rtx insn, rtx link, rtx dep_insn, int cost);
255 /* Adjust the priority of an insn as you see fit. Returns the new
257 int (* adjust_priority) (rtx, int);
259 /* Function which returns the maximum number of insns that can be
260 scheduled in the same machine cycle. This must be constant
261 over an entire compilation. The default is 1. */
262 int (* issue_rate) (void);
264 /* Calculate how much this insn affects how many more insns we
265 can emit this cycle. Default is they all cost the same. */
266 int (* variable_issue) (FILE *, int, rtx, int);
268 /* Initialize machine-dependent scheduling code. */
269 void (* md_init) (FILE *, int, int);
271 /* Finalize machine-dependent scheduling code. */
272 void (* md_finish) (FILE *, int);
274 /* Initialize machine-dependent function while scheduling code. */
275 void (* md_init_global) (FILE *, int, int);
277 /* Finalize machine-dependent function wide scheduling code. */
278 void (* md_finish_global) (FILE *, int);
280 /* Reorder insns in a machine-dependent fashion, in two different
281 places. Default does nothing. */
282 int (* reorder) (FILE *, int, rtx *, int *, int);
283 int (* reorder2) (FILE *, int, rtx *, int *, int);
285 /* The following member value is a pointer to a function called
286 after evaluation forward dependencies of insns in chain given
287 by two parameter values (head and tail correspondingly). */
288 void (* dependencies_evaluation_hook) (rtx, rtx);
290 /* The values of the following four members are pointers to
291 functions used to simplify the automaton descriptions.
292 dfa_pre_cycle_insn and dfa_post_cycle_insn give functions
293 returning insns which are used to change the pipeline hazard
294 recognizer state when the new simulated processor cycle
295 correspondingly starts and finishes. The function defined by
296 init_dfa_pre_cycle_insn and init_dfa_post_cycle_insn are used
297 to initialize the corresponding insns. The default values of
298 the members result in not changing the automaton state when
299 the new simulated processor cycle correspondingly starts and
301 void (* init_dfa_pre_cycle_insn) (void);
302 rtx (* dfa_pre_cycle_insn) (void);
303 void (* init_dfa_post_cycle_insn) (void);
304 rtx (* dfa_post_cycle_insn) (void);
306 /* The values of the following two members are pointers to
307 functions used to simplify the automaton descriptions.
308 dfa_pre_advance_cycle and dfa_post_advance_cycle are getting called
309 immediatelly before and after cycle is advanced. */
310 void (* dfa_pre_advance_cycle) (void);
311 void (* dfa_post_advance_cycle) (void);
313 /* The following member value is a pointer to a function returning value
314 which defines how many insns in queue `ready' will we try for
315 multi-pass scheduling. If the member value is nonzero and the
316 function returns positive value, the DFA based scheduler will make
317 multi-pass scheduling for the first cycle. In other words, we will
318 try to choose ready insn which permits to start maximum number of
319 insns on the same cycle. */
320 int (* first_cycle_multipass_dfa_lookahead) (void);
322 /* The following member value is pointer to a function controlling
323 what insns from the ready insn queue will be considered for the
324 multipass insn scheduling. If the hook returns zero for insn
325 passed as the parameter, the insn will be not chosen to be
327 int (* first_cycle_multipass_dfa_lookahead_guard) (rtx);
329 /* The following member value is pointer to a function called by
330 the insn scheduler before issuing insn passed as the third
331 parameter on given cycle. If the hook returns nonzero, the
332 insn is not issued on given processors cycle. Instead of that,
333 the processor cycle is advanced. If the value passed through
334 the last parameter is zero, the insn ready queue is not sorted
335 on the new cycle start as usually. The first parameter passes
336 file for debugging output. The second one passes the scheduler
337 verbose level of the debugging output. The forth and the fifth
338 parameter values are correspondingly processor cycle on which
339 the previous insn has been issued and the current processor
341 int (* dfa_new_cycle) (FILE *, int, rtx, int, int, int *);
343 /* The following member value is a pointer to a function called by the
344 insn scheduler. It should return true if there exists a dependence
345 which is considered costly by the target, between the insn
346 DEP_PRO (&_DEP), and the insn DEP_CON (&_DEP). The first parameter is
347 the dep that represents the dependence between the two insns. The
348 second argument is the cost of the dependence as estimated by
349 the scheduler. The last argument is the distance in cycles
350 between the already scheduled insn (first parameter) and the
351 the second insn (second parameter). */
352 bool (* is_costly_dependence) (struct _dep *_dep, int, int);
354 /* The following member value is a pointer to a function called
355 by the insn scheduler. This hook is called to notify the backend
356 that new instructions were emitted. */
357 void (* h_i_d_extended) (void);
359 /* The following member value is a pointer to a function called
360 by the insn scheduler.
361 The first parameter is an instruction, the second parameter is the type
362 of the requested speculation, and the third parameter is a pointer to the
363 speculative pattern of the corresponding type (set if return value == 1).
365 -1, if there is no pattern, that will satisfy the requested speculation
367 0, if current pattern satisfies the requested speculation type,
368 1, if pattern of the instruction should be changed to the newly
370 int (* speculate_insn) (rtx, int, rtx *);
372 /* The following member value is a pointer to a function called
373 by the insn scheduler. It should return true if the check instruction
374 corresponding to the instruction passed as the parameter needs a
376 bool (* needs_block_p) (const_rtx);
378 /* The following member value is a pointer to a function called
379 by the insn scheduler. It should return a pattern for the check
381 The first parameter is a speculative instruction, the second parameter
382 is the label of the corresponding recovery block (or null, if it is a
383 simple check). If the mutation of the check is requested (e.g. from
384 ld.c to chk.a), the third parameter is true - in this case the first
385 parameter is the previous check. */
386 rtx (* gen_check) (rtx, rtx, bool);
388 /* The following member value is a pointer to a function controlling
389 what insns from the ready insn queue will be considered for the
390 multipass insn scheduling. If the hook returns zero for the insn
391 passed as the parameter, the insn will not be chosen to be
392 issued. This hook is used to discard speculative instructions,
393 that stand at the first position of the ready list. */
394 bool (* first_cycle_multipass_dfa_lookahead_guard_spec) (const_rtx);
396 /* The following member value is a pointer to a function that provides
397 information about the speculation capabilities of the target.
398 The parameter is a pointer to spec_info variable. */
399 void (* set_sched_flags) (struct spec_info_def *);
402 /* Functions relating to vectorization. */
405 /* The following member value is a pointer to a function called
406 by the vectorizer, and return the decl of the target builtin
408 tree (* builtin_mask_for_load) (void);
410 /* Returns a code for builtin that realizes vectorized version of
411 function, or NULL_TREE if not available. */
412 tree (* builtin_vectorized_function) (unsigned, tree, tree);
414 /* Returns a code for builtin that realizes vectorized version of
415 conversion, or NULL_TREE if not available. */
416 tree (* builtin_conversion) (unsigned, tree);
418 /* Target builtin that implements vector widening multiplication.
419 builtin_mul_widen_eve computes the element-by-element products
420 for the even elements, and builtin_mul_widen_odd computes the
421 element-by-element products for the odd elements. */
422 tree (* builtin_mul_widen_even) (tree);
423 tree (* builtin_mul_widen_odd) (tree);
425 /* Returns the cost to be added to the overheads involved with
426 executing the vectorized version of a loop. */
427 int (*builtin_vectorization_cost) (bool);
429 /* Return true if vector alignment is reachable (by peeling N
430 iterations) for the given type. */
431 bool (* vector_alignment_reachable) (const_tree, bool);
434 /* The initial value of target_flags. */
435 int default_target_flags;
437 /* Handle target switch CODE (an OPT_* value). ARG is the argument
438 passed to the switch; it is NULL if no argument was. VALUE is the
439 value of ARG if CODE specifies a UInteger option, otherwise it is
440 1 if the positive form of the switch was used and 0 if the negative
441 form was. Return true if the switch was valid. */
442 bool (* handle_option) (size_t code, const char *arg, int value);
444 /* Display extra, target specific information in response to a
445 --target-help switch. */
446 void (* target_help) (void);
448 /* Return machine mode for filter value. */
449 enum machine_mode (* eh_return_filter_mode) (void);
451 /* Return machine mode for libgcc expanded cmp instructions. */
452 enum machine_mode (* libgcc_cmp_return_mode) (void);
454 /* Return machine mode for libgcc expanded shift instructions. */
455 enum machine_mode (* libgcc_shift_count_mode) (void);
457 /* Given two decls, merge their attributes and return the result. */
458 tree (* merge_decl_attributes) (tree, tree);
460 /* Given two types, merge their attributes and return the result. */
461 tree (* merge_type_attributes) (tree, tree);
463 /* Table of machine attributes and functions to handle them.
465 const struct attribute_spec *attribute_table;
467 /* Return zero if the attributes on TYPE1 and TYPE2 are incompatible,
468 one if they are compatible and two if they are nearly compatible
469 (which causes a warning to be generated). */
470 int (* comp_type_attributes) (const_tree type1, const_tree type2);
472 /* Assign default attributes to the newly defined TYPE. */
473 void (* set_default_type_attributes) (tree type);
475 /* Insert attributes on the newly created DECL. */
476 void (* insert_attributes) (tree decl, tree *attributes);
478 /* Return true if FNDECL (which has at least one machine attribute)
479 can be inlined despite its machine attributes, false otherwise. */
480 bool (* function_attribute_inlinable_p) (const_tree fndecl);
482 /* Return true if bitfields in RECORD_TYPE should follow the
483 Microsoft Visual C++ bitfield layout rules. */
484 bool (* ms_bitfield_layout_p) (const_tree record_type);
486 /* True if the target supports decimal floating point. */
487 bool (* decimal_float_supported_p) (void);
489 /* True if the target supports fixed-point. */
490 bool (* fixed_point_supported_p) (void);
492 /* Return true if anonymous bitfields affect structure alignment. */
493 bool (* align_anon_bitfield) (void);
495 /* Return true if volatile bitfields should use the narrowest type possible.
496 Return false if they should use the container type. */
497 bool (* narrow_volatile_bitfield) (void);
499 /* Set up target-specific built-in functions. */
500 void (* init_builtins) (void);
502 /* Expand a target-specific builtin. */
503 rtx (* expand_builtin) (tree exp, rtx target, rtx subtarget,
504 enum machine_mode mode, int ignore);
506 /* Select a replacement for a target-specific builtin. This is done
507 *before* regular type checking, and so allows the target to implement
508 a crude form of function overloading. The result is a complete
509 expression that implements the operation. */
510 tree (*resolve_overloaded_builtin) (tree decl, tree params);
512 /* Fold a target-specific builtin. */
513 tree (* fold_builtin) (tree fndecl, tree arglist, bool ignore);
515 /* Returns a code for a target-specific builtin that implements
516 reciprocal of the function, or NULL_TREE if not available. */
517 tree (* builtin_reciprocal) (unsigned, bool, bool);
519 /* For a vendor-specific TYPE, return a pointer to a statically-allocated
520 string containing the C++ mangling for TYPE. In all other cases, return
522 const char * (* mangle_type) (const_tree type);
524 /* Make any adjustments to libfunc names needed for this target. */
525 void (* init_libfuncs) (void);
527 /* Given a decl, a section name, and whether the decl initializer
528 has relocs, choose attributes for the section. */
529 /* ??? Should be merged with SELECT_SECTION and UNIQUE_SECTION. */
530 unsigned int (* section_type_flags) (tree, const char *, int);
532 /* True if new jumps cannot be created, to replace existing ones or
533 not, at the current point in the compilation. */
534 bool (* cannot_modify_jumps_p) (void);
536 /* Return a register class for which branch target register
537 optimizations should be applied. */
538 int (* branch_target_register_class) (void);
540 /* Return true if branch target register optimizations should include
541 callee-saved registers that are not already live during the current
542 function. AFTER_PE_GEN is true if prologues and epilogues have
543 already been generated. */
544 bool (* branch_target_register_callee_saved) (bool after_pe_gen);
546 /* True if the constant X cannot be placed in the constant pool. */
547 bool (* cannot_force_const_mem) (rtx);
549 /* True if the insn X cannot be duplicated. */
550 bool (* cannot_copy_insn_p) (rtx);
552 /* True if X is considered to be commutative. */
553 bool (* commutative_p) (const_rtx, int);
555 /* Given an address RTX, undo the effects of LEGITIMIZE_ADDRESS. */
556 rtx (* delegitimize_address) (rtx);
558 /* True if the given constant can be put into an object_block. */
559 bool (* use_blocks_for_constant_p) (enum machine_mode, const_rtx);
561 /* The minimum and maximum byte offsets for anchored addresses. */
562 HOST_WIDE_INT min_anchor_offset;
563 HOST_WIDE_INT max_anchor_offset;
565 /* True if section anchors can be used to access the given symbol. */
566 bool (* use_anchors_for_symbol_p) (const_rtx);
568 /* True if it is OK to do sibling call optimization for the specified
569 call expression EXP. DECL will be the called function, or NULL if
570 this is an indirect call. */
571 bool (*function_ok_for_sibcall) (tree decl, tree exp);
573 /* True if EXP should be placed in a "small data" section. */
574 bool (* in_small_data_p) (const_tree);
576 /* True if EXP names an object for which name resolution must resolve
577 to the current module. */
578 bool (* binds_local_p) (const_tree);
580 /* Modify and return the identifier of a DECL's external name,
581 originally identified by ID, as required by the target,
582 (eg, append @nn to windows32 stdcall function names).
583 The default is to return ID without modification. */
584 tree (* mangle_decl_assembler_name) (tree decl, tree id);
586 /* Do something target-specific to record properties of the DECL into
587 the associated SYMBOL_REF. */
588 void (* encode_section_info) (tree, rtx, int);
590 /* Undo the effects of encode_section_info on the symbol string. */
591 const char * (* strip_name_encoding) (const char *);
593 /* If shift optabs for MODE are known to always truncate the shift count,
594 return the mask that they apply. Return 0 otherwise. */
595 unsigned HOST_WIDE_INT (* shift_truncation_mask) (enum machine_mode mode);
597 /* Return the number of divisions in the given MODE that should be present,
598 so that it is profitable to turn the division into a multiplication by
600 unsigned int (* min_divisions_for_recip_mul) (enum machine_mode mode);
602 /* If the representation of integral MODE is such that values are
603 always sign-extended to a wider mode MODE_REP then return
604 SIGN_EXTEND. Return UNKNOWN otherwise. */
605 /* Note that the return type ought to be RTX_CODE, but that's not
606 necessarily defined at this point. */
607 int (* mode_rep_extended) (enum machine_mode mode,
608 enum machine_mode mode_rep);
610 /* True if MODE is valid for a pointer in __attribute__((mode("MODE"))). */
611 bool (* valid_pointer_mode) (enum machine_mode mode);
613 /* True if MODE is valid for the target. By "valid", we mean able to
614 be manipulated in non-trivial ways. In particular, this means all
615 the arithmetic is supported. */
616 bool (* scalar_mode_supported_p) (enum machine_mode mode);
618 /* Similarly for vector modes. "Supported" here is less strict. At
619 least some operations are supported; need to check optabs or builtins
620 for further details. */
621 bool (* vector_mode_supported_p) (enum machine_mode mode);
623 /* True if a vector is opaque. */
624 bool (* vector_opaque_p) (const_tree);
626 /* Compute a (partial) cost for rtx X. Return true if the complete
627 cost has been computed, and false if subexpressions should be
628 scanned. In either case, *TOTAL contains the cost result. */
629 /* Note that CODE and OUTER_CODE ought to be RTX_CODE, but that's
630 not necessarily defined at this point. */
631 bool (* rtx_costs) (rtx x, int code, int outer_code, int *total);
633 /* Compute the cost of X, used as an address. Never called with
634 invalid addresses. */
635 int (* address_cost) (rtx x);
637 /* Return where to allocate pseudo for a given hard register initial
639 rtx (* allocate_initial_value) (rtx x);
641 /* Given a register, this hook should return a parallel of registers
642 to represent where to find the register pieces. Define this hook
643 if the register and its mode are represented in Dwarf in
644 non-contiguous locations, or if the register should be
645 represented in more than one register in Dwarf. Otherwise, this
646 hook should return NULL_RTX. */
647 rtx (* dwarf_register_span) (rtx);
649 /* If expand_builtin_init_dwarf_reg_sizes needs to fill in table
650 entries not corresponding directly to registers below
651 FIRST_PSEUDO_REGISTER, this hook should generate the necessary
652 code, given the address of the table. */
653 void (* init_dwarf_reg_sizes_extra) (tree);
655 /* Fetch the fixed register(s) which hold condition codes, for
656 targets where it makes sense to look for duplicate assignments to
657 the condition codes. This should return true if there is such a
658 register, false otherwise. The arguments should be set to the
659 fixed register numbers. Up to two condition code registers are
660 supported. If there is only one for this target, the int pointed
661 at by the second argument should be set to -1. */
662 bool (* fixed_condition_code_regs) (unsigned int *, unsigned int *);
664 /* If two condition code modes are compatible, return a condition
665 code mode which is compatible with both, such that a comparison
666 done in the returned mode will work for both of the original
667 modes. If the condition code modes are not compatible, return
669 enum machine_mode (* cc_modes_compatible) (enum machine_mode,
672 /* Do machine-dependent code transformations. Called just before
673 delayed-branch scheduling. */
674 void (* machine_dependent_reorg) (void);
676 /* Create the __builtin_va_list type. */
677 tree (* build_builtin_va_list) (void);
679 /* Gimplifies a VA_ARG_EXPR. */
680 tree (* gimplify_va_arg_expr) (tree valist, tree type, tree *pre_p,
683 /* Validity-checking routines for PCH files, target-specific.
684 get_pch_validity returns a pointer to the data to be stored,
685 and stores the size in its argument. pch_valid_p gets the same
686 information back and returns NULL if the PCH is valid,
687 or an error message if not.
689 void * (* get_pch_validity) (size_t *);
690 const char * (* pch_valid_p) (const void *, size_t);
692 /* If nonnull, this function checks whether a PCH file with the
693 given set of target flags can be used. It returns NULL if so,
694 otherwise it returns an error message. */
695 const char *(*check_pch_target_flags) (int);
697 /* True if the compiler should give an enum type only as many
698 bytes as it takes to represent the range of possible values of
700 bool (* default_short_enums) (void);
702 /* This target hook returns an rtx that is used to store the address
703 of the current frame into the built-in setjmp buffer. */
704 rtx (* builtin_setjmp_frame_value) (void);
706 /* This target hook should add STRING_CST trees for any hard regs
707 the port wishes to automatically clobber for an asm. */
708 tree (* md_asm_clobbers) (tree, tree, tree);
710 /* This target hook allows the backend to specify a calling convention
711 in the debug information. This function actually returns an
712 enum dwarf_calling_convention, but because of forward declarations
713 and not wanting to include dwarf2.h everywhere target.h is included
714 the function is being declared as an int. */
715 int (* dwarf_calling_convention) (const_tree);
717 /* This target hook allows the backend to emit frame-related insns that
718 contain UNSPECs or UNSPEC_VOLATILEs. The call frame debugging info
719 engine will invoke it on insns of the form
720 (set (reg) (unspec [...] UNSPEC_INDEX))
722 (set (reg) (unspec_volatile [...] UNSPECV_INDEX))
723 to let the backend emit the call frame instructions. */
724 void (* dwarf_handle_frame_unspec) (const char *, rtx, int);
726 /* Perform architecture specific checking of statements gimplified
727 from VA_ARG_EXPR. LHS is left hand side of MODIFY_EXPR, RHS
728 is right hand side. Returns true if the statements doesn't need
729 to be checked for va_list references. */
730 bool (* stdarg_optimize_hook) (struct stdarg_info *ai, const_tree lhs, const_tree rhs);
732 /* This target hook allows the operating system to override the DECL
733 that represents the external variable that contains the stack
734 protection guard variable. The type of this DECL is ptr_type_node. */
735 tree (* stack_protect_guard) (void);
737 /* This target hook allows the operating system to override the CALL_EXPR
738 that is invoked when a check vs the guard variable fails. */
739 tree (* stack_protect_fail) (void);
741 /* Returns NULL if target supports the insn within a doloop block,
742 otherwise it returns an error message. */
743 const char * (*invalid_within_doloop) (const_rtx);
745 /* DECL is a variable or function with __attribute__((dllimport))
746 specified. Use this hook if the target needs to add extra validation
747 checks to handle_dll_attribute (). */
748 bool (* valid_dllimport_attribute_p) (const_tree decl);
750 /* Functions relating to calls - argument passing, returns, etc. */
752 bool (*promote_function_args) (const_tree fntype);
753 bool (*promote_function_return) (const_tree fntype);
754 bool (*promote_prototypes) (const_tree fntype);
755 rtx (*struct_value_rtx) (tree fndecl, int incoming);
756 bool (*return_in_memory) (const_tree type, const_tree fndecl);
757 bool (*return_in_msb) (const_tree type);
759 /* Return true if a parameter must be passed by reference. TYPE may
760 be null if this is a libcall. CA may be null if this query is
761 from __builtin_va_arg. */
762 bool (*pass_by_reference) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
763 const_tree type, bool named_arg);
765 rtx (*expand_builtin_saveregs) (void);
766 /* Returns pretend_argument_size. */
767 void (*setup_incoming_varargs) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
768 tree type, int *pretend_arg_size,
770 bool (*strict_argument_naming) (CUMULATIVE_ARGS *ca);
771 /* Returns true if we should use
772 targetm.calls.setup_incoming_varargs() and/or
773 targetm.calls.strict_argument_naming(). */
774 bool (*pretend_outgoing_varargs_named) (CUMULATIVE_ARGS *ca);
776 /* Given a complex type T, return true if a parameter of type T
777 should be passed as two scalars. */
778 bool (* split_complex_arg) (const_tree type);
780 /* Return true if type T, mode MODE, may not be passed in registers,
781 but must be passed on the stack. */
782 /* ??? This predicate should be applied strictly after pass-by-reference.
783 Need audit to verify that this is the case. */
784 bool (* must_pass_in_stack) (enum machine_mode mode, const_tree t);
786 /* Return true if type TYPE, mode MODE, which is passed by reference,
787 should have the object copy generated by the callee rather than
788 the caller. It is never called for TYPE requiring constructors. */
789 bool (* callee_copies) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
790 const_tree type, bool named);
792 /* Return zero for arguments passed entirely on the stack or entirely
793 in registers. If passed in both, return the number of bytes passed
794 in registers; the balance is therefore passed on the stack. */
795 int (* arg_partial_bytes) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
796 tree type, bool named);
798 /* Return the diagnostic message string if function without a prototype
799 is not allowed for this 'val' argument; NULL otherwise. */
800 const char *(*invalid_arg_for_unprototyped_fn) (const_tree typelist,
804 /* Return an rtx for the return value location of the function
805 specified by FN_DECL_OR_TYPE with a return type of RET_TYPE. */
806 rtx (*function_value) (const_tree ret_type, const_tree fn_decl_or_type,
809 /* Return an rtx for the argument pointer incoming to the
811 rtx (*internal_arg_pointer) (void);
814 /* Return the diagnostic message string if conversion from FROMTYPE
815 to TOTYPE is not allowed, NULL otherwise. */
816 const char *(*invalid_conversion) (const_tree fromtype, const_tree totype);
818 /* Return the diagnostic message string if the unary operation OP is
819 not permitted on TYPE, NULL otherwise. */
820 const char *(*invalid_unary_op) (int op, const_tree type);
822 /* Return the diagnostic message string if the binary operation OP
823 is not permitted on TYPE1 and TYPE2, NULL otherwise. */
824 const char *(*invalid_binary_op) (int op, const_tree type1, const_tree type2);
826 /* Return the class for a secondary reload, and fill in extra information. */
827 enum reg_class (*secondary_reload) (bool, rtx, enum reg_class,
829 struct secondary_reload_info *);
831 /* Functions specific to the C family of frontends. */
833 /* Return machine mode for non-standard suffix
834 or VOIDmode if non-standard suffixes are unsupported. */
835 enum machine_mode (*mode_for_suffix) (char);
838 /* Functions specific to the C++ frontend. */
840 /* Return the integer type used for guard variables. */
841 tree (*guard_type) (void);
842 /* Return true if only the low bit of the guard should be tested. */
843 bool (*guard_mask_bit) (void);
844 /* Returns the size of the array cookie for an array of type. */
845 tree (*get_cookie_size) (tree);
846 /* Returns true if the element size should be stored in the
848 bool (*cookie_has_size) (void);
849 /* Allows backends to perform additional processing when
850 deciding if a class should be exported or imported. */
851 int (*import_export_class) (tree, int);
852 /* Returns true if constructors and destructors return "this". */
853 bool (*cdtor_returns_this) (void);
854 /* Returns true if the key method for a class can be an inline
855 function, so long as it is not declared inline in the class
856 itself. Returning true is the behavior required by the Itanium
858 bool (*key_method_may_be_inline) (void);
859 /* DECL is a virtual table, virtual table table, typeinfo object,
860 or other similar implicit class data object that will be
861 emitted with external linkage in this translation unit. No ELF
862 visibility has been explicitly specified. If the target needs
863 to specify a visibility other than that of the containing class,
864 use this hook to set DECL_VISIBILITY and
865 DECL_VISIBILITY_SPECIFIED. */
866 void (*determine_class_data_visibility) (tree decl);
867 /* Returns true (the default) if virtual tables and other
868 similar implicit class data objects are always COMDAT if they
869 have external linkage. If this hook returns false, then
870 class data for classes whose virtual table will be emitted in
871 only one translation unit will not be COMDAT. */
872 bool (*class_data_always_comdat) (void);
873 /* Returns true (the default) if the RTTI for the basic types,
874 which is always defined in the C++ runtime, should be COMDAT;
875 false if it should not be COMDAT. */
876 bool (*library_rtti_comdat) (void);
877 /* Returns true if __aeabi_atexit should be used to register static
879 bool (*use_aeabi_atexit) (void);
880 /* Returns true if target may use atexit in the same manner as
881 __cxa_atexit to register static destructors. */
882 bool (*use_atexit_for_cxa_atexit) (void);
883 /* TYPE is a C++ class (i.e., RECORD_TYPE or UNION_TYPE) that
884 has just been defined. Use this hook to make adjustments to the
885 class (eg, tweak visibility or perform any other required
886 target modifications). */
887 void (*adjust_class_at_definition) (tree type);
890 /* For targets that need to mark extra registers as live on entry to
891 the function, they should define this target hook and set their
892 bits in the bitmap passed in. */
893 void (*live_on_entry) (bitmap);
895 /* True if unwinding tables should be generated by default. */
896 bool unwind_tables_default;
898 /* Leave the boolean fields at the end. */
900 /* True if arbitrary sections are supported. */
901 bool have_named_sections;
903 /* True if we can create zeroed data by switching to a BSS section
904 and then using ASM_OUTPUT_SKIP to allocate the space. */
905 bool have_switchable_bss_sections;
907 /* True if "native" constructors and destructors are supported,
908 false if we're using collect2 for the job. */
909 bool have_ctors_dtors;
911 /* True if thread-local storage is supported. */
914 /* True if a small readonly data section is supported. */
915 bool have_srodata_section;
917 /* True if EH frame info sections should be zero-terminated. */
918 bool terminate_dw2_eh_frame_info;
920 /* True if #NO_APP should be emitted at the beginning of
922 bool file_start_app_off;
924 /* True if output_file_directive should be called for main_input_filename
925 at the beginning of assembly output. */
926 bool file_start_file_directive;
928 /* True if #pragma redefine_extname is to be supported. */
929 bool handle_pragma_redefine_extname;
931 /* True if #pragma extern_prefix is to be supported. */
932 bool handle_pragma_extern_prefix;
934 /* True if the target is allowed to reorder memory accesses unless
935 synchronization is explicitly requested. */
936 bool relaxed_ordering;
938 /* Returns true if we should generate exception tables for use with the
939 ARM EABI. The effects the encoding of function exception specifications.
941 bool arm_eabi_unwinder;
943 /* Leave the boolean fields at the end. */
946 extern struct gcc_target targetm;
948 struct gcc_targetcm {
949 /* Handle target switch CODE (an OPT_* value). ARG is the argument
950 passed to the switch; it is NULL if no argument was. VALUE is the
951 value of ARG if CODE specifies a UInteger option, otherwise it is
952 1 if the positive form of the switch was used and 0 if the negative
953 form was. Return true if the switch was valid. */
954 bool (*handle_c_option) (size_t code, const char *arg, int value);
957 /* Each target can provide their own. */
958 extern struct gcc_targetcm targetcm;
960 #endif /* GCC_TARGET_H */
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