1 /* Data structure definitions for a generic GCC target.
2 Copyright (C) 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
4 This program is free software; you can redistribute it and/or modify it
5 under the terms of the GNU General Public License as published by the
6 Free Software Foundation; either version 2, or (at your option) any
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, write to the Free Software
16 Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
18 In other words, you are welcome to use, share and improve this program.
19 You are forbidden to forbid anyone else to use, share and improve
20 what you give them. Help stamp out software-hoarding! */
22 /* This file contains a data structure that describes a GCC target.
23 At present it is incomplete, but in future it should grow to
24 contain most or all target machine and target O/S specific
27 This structure has its initializer declared in target-def.h in the
28 form of large macro TARGET_INITIALIZER that expands to many smaller
31 The smaller macros each initialize one component of the structure,
32 and each has a default. Each target should have a file that
33 includes target.h and target-def.h, and overrides any inappropriate
34 defaults by undefining the relevant macro and defining a suitable
35 replacement. That file should then contain the definition of
38 struct gcc_target targetm = TARGET_INITIALIZER;
40 Doing things this way allows us to bring together everything that
41 defines a GCC target. By supplying a default that is appropriate
42 to most targets, we can easily add new items without needing to
43 edit dozens of target configuration files. It should also allow us
44 to gradually reduce the amount of conditional compilation that is
45 scattered throughout GCC. */
51 #include "insn-modes.h"
56 /* The struct used by the secondary_reload target hook. */
57 typedef struct secondary_reload_info
59 /* icode is actually an enum insn_code, but we don't want to force every
60 file that includes target.h to include optabs.h . */
62 int extra_cost; /* Cost for using (a) scratch register(s) to be taken
63 into account by copy_cost. */
64 /* The next two members are for the use of the backward
65 compatibility hook. */
66 struct secondary_reload_info *prev_sri;
67 int t_icode; /* Actually an enum insn_code - see above. */
68 } secondary_reload_info;
73 /* Functions that output assembler for the target. */
76 /* Opening and closing parentheses for asm expression grouping. */
77 const char *open_paren, *close_paren;
79 /* Assembler instructions for creating various kinds of integer object. */
87 } aligned_op, unaligned_op;
89 /* Try to output the assembler code for an integer object whose
90 value is given by X. SIZE is the size of the object in bytes and
91 ALIGNED_P indicates whether it is aligned. Return true if
92 successful. Only handles cases for which BYTE_OP, ALIGNED_OP
93 and UNALIGNED_OP are NULL. */
94 bool (* integer) (rtx x, unsigned int size, int aligned_p);
96 /* Output code that will globalize a label. */
97 void (* globalize_label) (FILE *, const char *);
99 /* Output code that will emit a label for unwind info, if this
100 target requires such labels. Second argument is the decl the
101 unwind info is associated with, third is a boolean: true if
102 this is for exception handling, fourth is a boolean: true if
103 this is only a placeholder for an omitted FDE. */
104 void (* unwind_label) (FILE *, tree, int, int);
106 /* Output code that will emit a label to divide up the exception
108 void (* except_table_label) (FILE *);
110 /* Emit any directives required to unwind this instruction. */
111 void (* unwind_emit) (FILE *, rtx);
113 /* Output an internal label. */
114 void (* internal_label) (FILE *, const char *, unsigned long);
116 /* Emit a ttype table reference to a typeinfo object. */
117 bool (* ttype) (rtx);
119 /* Emit an assembler directive to set visibility for the symbol
120 associated with the tree decl. */
121 void (* visibility) (tree, int);
123 /* Output the assembler code for entry to a function. */
124 void (* function_prologue) (FILE *, HOST_WIDE_INT);
126 /* Output the assembler code for end of prologue. */
127 void (* function_end_prologue) (FILE *);
129 /* Output the assembler code for start of epilogue. */
130 void (* function_begin_epilogue) (FILE *);
132 /* Output the assembler code for function exit. */
133 void (* function_epilogue) (FILE *, HOST_WIDE_INT);
135 /* Initialize target-specific sections. */
136 void (* init_sections) (void);
138 /* Tell assembler to change to section NAME with attributes FLAGS.
139 If DECL is non-NULL, it is the VAR_DECL or FUNCTION_DECL with
140 which this section is associated. */
141 void (* named_section) (const char *name, unsigned int flags, tree decl);
143 /* Return a section for EXP. It may be a DECL or a constant. RELOC
144 is nonzero if runtime relocations must be applied; bit 1 will be
145 set if the runtime relocations require non-local name resolution.
146 ALIGN is the required alignment of the data. */
147 section *(* select_section) (tree, int, unsigned HOST_WIDE_INT);
149 /* Return a section for X. MODE is X's mode and ALIGN is its
150 alignment in bits. */
151 section *(* select_rtx_section) (enum machine_mode, rtx,
152 unsigned HOST_WIDE_INT);
154 /* Select a unique section name for DECL. RELOC is the same as
155 for SELECT_SECTION. */
156 void (* unique_section) (tree, int);
158 /* Return the readonly data section associated with function DECL. */
159 section *(* function_rodata_section) (tree);
161 /* Output a constructor for a symbol with a given priority. */
162 void (* constructor) (rtx, int);
164 /* Output a destructor for a symbol with a given priority. */
165 void (* destructor) (rtx, int);
167 /* Output the assembler code for a thunk function. THUNK_DECL is the
168 declaration for the thunk function itself, FUNCTION is the decl for
169 the target function. DELTA is an immediate constant offset to be
170 added to THIS. If VCALL_OFFSET is nonzero, the word at
171 *(*this + vcall_offset) should be added to THIS. */
172 void (* output_mi_thunk) (FILE *file, tree thunk_decl,
173 HOST_WIDE_INT delta, HOST_WIDE_INT vcall_offset,
176 /* Determine whether output_mi_thunk would succeed. */
177 /* ??? Ideally, this hook would not exist, and success or failure
178 would be returned from output_mi_thunk directly. But there's
179 too much undo-able setup involved in invoking output_mi_thunk.
180 Could be fixed by making output_mi_thunk emit rtl instead of
181 text to the output file. */
182 bool (* can_output_mi_thunk) (tree thunk_decl, HOST_WIDE_INT delta,
183 HOST_WIDE_INT vcall_offset,
186 /* Output any boilerplate text needed at the beginning of a
188 void (*file_start) (void);
190 /* Output any boilerplate text needed at the end of a
192 void (*file_end) (void);
194 /* Output an assembler pseudo-op to declare a library function name
196 void (*external_libcall) (rtx);
198 /* Output an assembler directive to mark decl live. This instructs
199 linker to not dead code strip this symbol. */
200 void (*mark_decl_preserved) (const char *);
202 /* Output the definition of a section anchor. */
203 void (*output_anchor) (rtx);
205 /* Output a DTP-relative reference to a TLS symbol. */
206 void (*output_dwarf_dtprel) (FILE *file, int size, rtx x);
210 /* Functions relating to instruction scheduling. */
213 /* Given the current cost, COST, of an insn, INSN, calculate and
214 return a new cost based on its relationship to DEP_INSN through
215 the dependence LINK. The default is to make no adjustment. */
216 int (* adjust_cost) (rtx insn, rtx link, rtx def_insn, int cost);
218 /* Adjust the priority of an insn as you see fit. Returns the new
220 int (* adjust_priority) (rtx, int);
222 /* Function which returns the maximum number of insns that can be
223 scheduled in the same machine cycle. This must be constant
224 over an entire compilation. The default is 1. */
225 int (* issue_rate) (void);
227 /* Calculate how much this insn affects how many more insns we
228 can emit this cycle. Default is they all cost the same. */
229 int (* variable_issue) (FILE *, int, rtx, int);
231 /* Initialize machine-dependent scheduling code. */
232 void (* md_init) (FILE *, int, int);
234 /* Finalize machine-dependent scheduling code. */
235 void (* md_finish) (FILE *, int);
237 /* Initialize machine-dependent function while scheduling code. */
238 void (* md_init_global) (FILE *, int, int);
240 /* Finalize machine-dependent function wide scheduling code. */
241 void (* md_finish_global) (FILE *, int);
243 /* Reorder insns in a machine-dependent fashion, in two different
244 places. Default does nothing. */
245 int (* reorder) (FILE *, int, rtx *, int *, int);
246 int (* reorder2) (FILE *, int, rtx *, int *, int);
248 /* The following member value is a pointer to a function called
249 after evaluation forward dependencies of insns in chain given
250 by two parameter values (head and tail correspondingly). */
251 void (* dependencies_evaluation_hook) (rtx, rtx);
253 /* The values of the following four members are pointers to
254 functions used to simplify the automaton descriptions.
255 dfa_pre_cycle_insn and dfa_post_cycle_insn give functions
256 returning insns which are used to change the pipeline hazard
257 recognizer state when the new simulated processor cycle
258 correspondingly starts and finishes. The function defined by
259 init_dfa_pre_cycle_insn and init_dfa_post_cycle_insn are used
260 to initialize the corresponding insns. The default values of
261 the members result in not changing the automaton state when
262 the new simulated processor cycle correspondingly starts and
264 void (* init_dfa_pre_cycle_insn) (void);
265 rtx (* dfa_pre_cycle_insn) (void);
266 void (* init_dfa_post_cycle_insn) (void);
267 rtx (* dfa_post_cycle_insn) (void);
269 /* The following member value is a pointer to a function returning value
270 which defines how many insns in queue `ready' will we try for
271 multi-pass scheduling. If the member value is nonzero and the
272 function returns positive value, the DFA based scheduler will make
273 multi-pass scheduling for the first cycle. In other words, we will
274 try to choose ready insn which permits to start maximum number of
275 insns on the same cycle. */
276 int (* first_cycle_multipass_dfa_lookahead) (void);
278 /* The following member value is pointer to a function controlling
279 what insns from the ready insn queue will be considered for the
280 multipass insn scheduling. If the hook returns zero for insn
281 passed as the parameter, the insn will be not chosen to be
283 int (* first_cycle_multipass_dfa_lookahead_guard) (rtx);
285 /* The following member value is pointer to a function called by
286 the insn scheduler before issuing insn passed as the third
287 parameter on given cycle. If the hook returns nonzero, the
288 insn is not issued on given processors cycle. Instead of that,
289 the processor cycle is advanced. If the value passed through
290 the last parameter is zero, the insn ready queue is not sorted
291 on the new cycle start as usually. The first parameter passes
292 file for debugging output. The second one passes the scheduler
293 verbose level of the debugging output. The forth and the fifth
294 parameter values are correspondingly processor cycle on which
295 the previous insn has been issued and the current processor
297 int (* dfa_new_cycle) (FILE *, int, rtx, int, int, int *);
299 /* The following member value is a pointer to a function called
300 by the insn scheduler. It should return true if there exists a
301 dependence which is considered costly by the target, between
302 the insn passed as the first parameter, and the insn passed as
303 the second parameter. The third parameter is the INSN_DEPEND
304 link that represents the dependence between the two insns. The
305 fourth argument is the cost of the dependence as estimated by
306 the scheduler. The last argument is the distance in cycles
307 between the already scheduled insn (first parameter) and the
308 the second insn (second parameter). */
309 bool (* is_costly_dependence) (rtx, rtx, rtx, int, int);
311 /* Given the current cost, COST, of an insn, INSN, calculate and
312 return a new cost based on its relationship to DEP_INSN through the
313 dependence of type DEP_TYPE. The default is to make no adjustment. */
314 int (* adjust_cost_2) (rtx insn, int, rtx def_insn, int cost);
316 /* The following member value is a pointer to a function called
317 by the insn scheduler. This hook is called to notify the backend
318 that new instructions were emitted. */
319 void (* h_i_d_extended) (void);
321 /* The following member value is a pointer to a function called
322 by the insn scheduler.
323 The first parameter is an instruction, the second parameter is the type
324 of the requested speculation, and the third parameter is a pointer to the
325 speculative pattern of the corresponding type (set if return value == 1).
327 -1, if there is no pattern, that will satisfy the requested speculation
329 0, if current pattern satisfies the requested speculation type,
330 1, if pattern of the instruction should be changed to the newly
332 int (* speculate_insn) (rtx, HOST_WIDE_INT, rtx *);
334 /* The following member value is a pointer to a function called
335 by the insn scheduler. It should return true if the check instruction
336 corresponding to the instruction passed as the parameter needs a
338 bool (* needs_block_p) (rtx);
340 /* The following member value is a pointer to a function called
341 by the insn scheduler. It should return a pattern for the check
343 The first parameter is a speculative instruction, the second parameter
344 is the label of the corresponding recovery block (or null, if it is a
345 simple check). If the mutation of the check is requested (e.g. from
346 ld.c to chk.a), the third parameter is true - in this case the first
347 parameter is the previous check. */
348 rtx (* gen_check) (rtx, rtx, bool);
350 /* The following member value is a pointer to a function controlling
351 what insns from the ready insn queue will be considered for the
352 multipass insn scheduling. If the hook returns zero for the insn
353 passed as the parameter, the insn will not be chosen to be
354 issued. This hook is used to discard speculative instructions,
355 that stand at the first position of the ready list. */
356 bool (* first_cycle_multipass_dfa_lookahead_guard_spec) (rtx);
358 /* The following member value is a pointer to a function that provides
359 information about the speculation capabilities of the target.
360 The parameter is a pointer to spec_info variable. */
361 void (* set_sched_flags) (struct spec_info_def *);
364 /* Functions relating to vectorization. */
367 /* The following member value is a pointer to a function called
368 by the vectorizer, and return the decl of the target builtin
370 tree (* builtin_mask_for_load) (void);
373 /* The initial value of target_flags. */
374 int default_target_flags;
376 /* Handle target switch CODE (an OPT_* value). ARG is the argument
377 passed to the switch; it is NULL if no argument was. VALUE is the
378 value of ARG if CODE specifies a UInteger option, otherwise it is
379 1 if the positive form of the switch was used and 0 if the negative
380 form was. Return true if the switch was valid. */
381 bool (* handle_option) (size_t code, const char *arg, int value);
383 /* Return machine mode for filter value. */
384 enum machine_mode (* eh_return_filter_mode) (void);
386 /* Given two decls, merge their attributes and return the result. */
387 tree (* merge_decl_attributes) (tree, tree);
389 /* Given two types, merge their attributes and return the result. */
390 tree (* merge_type_attributes) (tree, tree);
392 /* Table of machine attributes and functions to handle them.
394 const struct attribute_spec *attribute_table;
396 /* Return zero if the attributes on TYPE1 and TYPE2 are incompatible,
397 one if they are compatible and two if they are nearly compatible
398 (which causes a warning to be generated). */
399 int (* comp_type_attributes) (tree type1, tree type2);
401 /* Assign default attributes to the newly defined TYPE. */
402 void (* set_default_type_attributes) (tree type);
404 /* Insert attributes on the newly created DECL. */
405 void (* insert_attributes) (tree decl, tree *attributes);
407 /* Return true if FNDECL (which has at least one machine attribute)
408 can be inlined despite its machine attributes, false otherwise. */
409 bool (* function_attribute_inlinable_p) (tree fndecl);
411 /* Return true if bitfields in RECORD_TYPE should follow the
412 Microsoft Visual C++ bitfield layout rules. */
413 bool (* ms_bitfield_layout_p) (tree record_type);
415 /* True if the target supports decimal floating point. */
416 bool (* decimal_float_supported_p) (void);
418 /* Return true if anonymous bitfields affect structure alignment. */
419 bool (* align_anon_bitfield) (void);
421 /* Return true if volatile bitfields should use the narrowest type possible.
422 Return false if they should use the container type. */
423 bool (* narrow_volatile_bitfield) (void);
425 /* Set up target-specific built-in functions. */
426 void (* init_builtins) (void);
428 /* Expand a target-specific builtin. */
429 rtx (* expand_builtin) (tree exp, rtx target, rtx subtarget,
430 enum machine_mode mode, int ignore);
432 /* Expand a target-specific library builtin. */
433 rtx (* expand_library_builtin) (tree exp, rtx target, rtx subtarget,
434 enum machine_mode mode, int ignore);
436 /* Select a replacement for a target-specific builtin. This is done
437 *before* regular type checking, and so allows the target to implement
438 a crude form of function overloading. The result is a complete
439 expression that implements the operation. */
440 tree (*resolve_overloaded_builtin) (tree decl, tree params);
442 /* Fold a target-specific builtin. */
443 tree (* fold_builtin) (tree fndecl, tree arglist, bool ignore);
445 /* For a vendor-specific fundamental TYPE, return a pointer to
446 a statically-allocated string containing the C++ mangling for
447 TYPE. In all other cases, return NULL. */
448 const char * (* mangle_fundamental_type) (tree type);
450 /* Make any adjustments to libfunc names needed for this target. */
451 void (* init_libfuncs) (void);
453 /* Given a decl, a section name, and whether the decl initializer
454 has relocs, choose attributes for the section. */
455 /* ??? Should be merged with SELECT_SECTION and UNIQUE_SECTION. */
456 unsigned int (* section_type_flags) (tree, const char *, int);
458 /* True if new jumps cannot be created, to replace existing ones or
459 not, at the current point in the compilation. */
460 bool (* cannot_modify_jumps_p) (void);
462 /* Return a register class for which branch target register
463 optimizations should be applied. */
464 int (* branch_target_register_class) (void);
466 /* Return true if branch target register optimizations should include
467 callee-saved registers that are not already live during the current
468 function. AFTER_PE_GEN is true if prologues and epilogues have
469 already been generated. */
470 bool (* branch_target_register_callee_saved) (bool after_pe_gen);
472 /* True if the constant X cannot be placed in the constant pool. */
473 bool (* cannot_force_const_mem) (rtx);
475 /* True if the insn X cannot be duplicated. */
476 bool (* cannot_copy_insn_p) (rtx);
478 /* True if X is considered to be commutative. */
479 bool (* commutative_p) (rtx, int);
481 /* Given an address RTX, undo the effects of LEGITIMIZE_ADDRESS. */
482 rtx (* delegitimize_address) (rtx);
484 /* True if the given constant can be put into an object_block. */
485 bool (* use_blocks_for_constant_p) (enum machine_mode, rtx);
487 /* The minimum and maximum byte offsets for anchored addresses. */
488 HOST_WIDE_INT min_anchor_offset;
489 HOST_WIDE_INT max_anchor_offset;
491 /* True if section anchors can be used to access the given symbol. */
492 bool (* use_anchors_for_symbol_p) (rtx);
494 /* True if it is OK to do sibling call optimization for the specified
495 call expression EXP. DECL will be the called function, or NULL if
496 this is an indirect call. */
497 bool (*function_ok_for_sibcall) (tree decl, tree exp);
499 /* True if EXP should be placed in a "small data" section. */
500 bool (* in_small_data_p) (tree);
502 /* True if EXP names an object for which name resolution must resolve
503 to the current module. */
504 bool (* binds_local_p) (tree);
506 /* Do something target-specific to record properties of the DECL into
507 the associated SYMBOL_REF. */
508 void (* encode_section_info) (tree, rtx, int);
510 /* Undo the effects of encode_section_info on the symbol string. */
511 const char * (* strip_name_encoding) (const char *);
513 /* If shift optabs for MODE are known to always truncate the shift count,
514 return the mask that they apply. Return 0 otherwise. */
515 unsigned HOST_WIDE_INT (* shift_truncation_mask) (enum machine_mode mode);
517 /* Return the number of divisions in the given MODE that should be present,
518 so that it is profitable to turn the division into a multiplication by
520 unsigned int (* min_divisions_for_recip_mul) (enum machine_mode mode);
522 /* True if MODE is valid for a pointer in __attribute__((mode("MODE"))). */
523 bool (* valid_pointer_mode) (enum machine_mode mode);
525 /* True if MODE is valid for the target. By "valid", we mean able to
526 be manipulated in non-trivial ways. In particular, this means all
527 the arithmetic is supported. */
528 bool (* scalar_mode_supported_p) (enum machine_mode mode);
530 /* Similarly for vector modes. "Supported" here is less strict. At
531 least some operations are supported; need to check optabs or builtins
532 for further details. */
533 bool (* vector_mode_supported_p) (enum machine_mode mode);
535 /* True if a vector is opaque. */
536 bool (* vector_opaque_p) (tree);
538 /* Compute a (partial) cost for rtx X. Return true if the complete
539 cost has been computed, and false if subexpressions should be
540 scanned. In either case, *TOTAL contains the cost result. */
541 /* Note that CODE and OUTER_CODE ought to be RTX_CODE, but that's
542 not necessarily defined at this point. */
543 bool (* rtx_costs) (rtx x, int code, int outer_code, int *total);
545 /* Compute the cost of X, used as an address. Never called with
546 invalid addresses. */
547 int (* address_cost) (rtx x);
549 /* Return where to allocate pseudo for a given hard register initial
551 rtx (* allocate_initial_value) (rtx x);
553 /* Given a register, this hook should return a parallel of registers
554 to represent where to find the register pieces. Define this hook
555 if the register and its mode are represented in Dwarf in
556 non-contiguous locations, or if the register should be
557 represented in more than one register in Dwarf. Otherwise, this
558 hook should return NULL_RTX. */
559 rtx (* dwarf_register_span) (rtx);
561 /* Fetch the fixed register(s) which hold condition codes, for
562 targets where it makes sense to look for duplicate assignments to
563 the condition codes. This should return true if there is such a
564 register, false otherwise. The arguments should be set to the
565 fixed register numbers. Up to two condition code registers are
566 supported. If there is only one for this target, the int pointed
567 at by the second argument should be set to -1. */
568 bool (* fixed_condition_code_regs) (unsigned int *, unsigned int *);
570 /* If two condition code modes are compatible, return a condition
571 code mode which is compatible with both, such that a comparison
572 done in the returned mode will work for both of the original
573 modes. If the condition code modes are not compatible, return
575 enum machine_mode (* cc_modes_compatible) (enum machine_mode,
578 /* Do machine-dependent code transformations. Called just before
579 delayed-branch scheduling. */
580 void (* machine_dependent_reorg) (void);
582 /* Create the __builtin_va_list type. */
583 tree (* build_builtin_va_list) (void);
585 /* Gimplifies a VA_ARG_EXPR. */
586 tree (* gimplify_va_arg_expr) (tree valist, tree type, tree *pre_p,
589 /* Validity-checking routines for PCH files, target-specific.
590 get_pch_validity returns a pointer to the data to be stored,
591 and stores the size in its argument. pch_valid_p gets the same
592 information back and returns NULL if the PCH is valid,
593 or an error message if not.
595 void * (* get_pch_validity) (size_t *);
596 const char * (* pch_valid_p) (const void *, size_t);
598 /* If nonnull, this function checks whether a PCH file with the
599 given set of target flags can be used. It returns NULL if so,
600 otherwise it returns an error message. */
601 const char *(*check_pch_target_flags) (int);
603 /* True if the compiler should give an enum type only as many
604 bytes as it takes to represent the range of possible values of
606 bool (* default_short_enums) (void);
608 /* This target hook returns an rtx that is used to store the address
609 of the current frame into the built-in setjmp buffer. */
610 rtx (* builtin_setjmp_frame_value) (void);
612 /* This target hook should add STRING_CST trees for any hard regs
613 the port wishes to automatically clobber for an asm. */
614 tree (* md_asm_clobbers) (tree, tree, tree);
616 /* This target hook allows the backend to specify a calling convention
617 in the debug information. This function actually returns an
618 enum dwarf_calling_convention, but because of forward declarations
619 and not wanting to include dwarf2.h everywhere target.h is included
620 the function is being declared as an int. */
621 int (* dwarf_calling_convention) (tree);
623 /* This target hook allows the backend to emit frame-related insns that
624 contain UNSPECs or UNSPEC_VOLATILEs. The call frame debugging info
625 engine will invoke it on insns of the form
626 (set (reg) (unspec [...] UNSPEC_INDEX))
628 (set (reg) (unspec_volatile [...] UNSPECV_INDEX))
629 to let the backend emit the call frame instructions. */
630 void (* dwarf_handle_frame_unspec) (const char *, rtx, int);
632 /* Perform architecture specific checking of statements gimplified
633 from VA_ARG_EXPR. LHS is left hand side of MODIFY_EXPR, RHS
634 is right hand side. Returns true if the statements doesn't need
635 to be checked for va_list references. */
636 bool (* stdarg_optimize_hook) (struct stdarg_info *ai, tree lhs, tree rhs);
638 /* This target hook allows the operating system to override the DECL
639 that represents the external variable that contains the stack
640 protection guard variable. The type of this DECL is ptr_type_node. */
641 tree (* stack_protect_guard) (void);
643 /* This target hook allows the operating system to override the CALL_EXPR
644 that is invoked when a check vs the guard variable fails. */
645 tree (* stack_protect_fail) (void);
647 /* Returns NULL if target supports the insn within a doloop block,
648 otherwise it returns an error message. */
649 const char * (*invalid_within_doloop) (rtx);
651 /* DECL is a variable or function with __attribute__((dllimport))
652 specified. Use this hook if the target needs to add extra validation
653 checks to handle_dll_attribute (). */
654 bool (* valid_dllimport_attribute_p) (tree decl);
656 /* Functions relating to calls - argument passing, returns, etc. */
658 bool (*promote_function_args) (tree fntype);
659 bool (*promote_function_return) (tree fntype);
660 bool (*promote_prototypes) (tree fntype);
661 rtx (*struct_value_rtx) (tree fndecl, int incoming);
662 bool (*return_in_memory) (tree type, tree fndecl);
663 bool (*return_in_msb) (tree type);
665 /* Return true if a parameter must be passed by reference. TYPE may
666 be null if this is a libcall. CA may be null if this query is
667 from __builtin_va_arg. */
668 bool (*pass_by_reference) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
669 tree type, bool named_arg);
671 rtx (*expand_builtin_saveregs) (void);
672 /* Returns pretend_argument_size. */
673 void (*setup_incoming_varargs) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
674 tree type, int *pretend_arg_size,
676 bool (*strict_argument_naming) (CUMULATIVE_ARGS *ca);
677 /* Returns true if we should use
678 targetm.calls.setup_incoming_varargs() and/or
679 targetm.calls.strict_argument_naming(). */
680 bool (*pretend_outgoing_varargs_named) (CUMULATIVE_ARGS *ca);
682 /* Given a complex type T, return true if a parameter of type T
683 should be passed as two scalars. */
684 bool (* split_complex_arg) (tree type);
686 /* Return true if type T, mode MODE, may not be passed in registers,
687 but must be passed on the stack. */
688 /* ??? This predicate should be applied strictly after pass-by-reference.
689 Need audit to verify that this is the case. */
690 bool (* must_pass_in_stack) (enum machine_mode mode, tree t);
692 /* Return true if type TYPE, mode MODE, which is passed by reference,
693 should have the object copy generated by the callee rather than
694 the caller. It is never called for TYPE requiring constructors. */
695 bool (* callee_copies) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
696 tree type, bool named);
698 /* Return zero for arguments passed entirely on the stack or entirely
699 in registers. If passed in both, return the number of bytes passed
700 in registers; the balance is therefore passed on the stack. */
701 int (* arg_partial_bytes) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
702 tree type, bool named);
704 /* Return the diagnostic message string if function without a prototype
705 is not allowed for this 'val' argument; NULL otherwise. */
706 const char *(*invalid_arg_for_unprototyped_fn) (tree typelist,
707 tree funcdecl, tree val);
709 /* Return an rtx for the return value location of the function
710 specified by FN_DECL_OR_TYPE with a return type of RET_TYPE. */
711 rtx (*function_value) (tree ret_type, tree fn_decl_or_type,
714 /* Return an rtx for the argument pointer incoming to the
716 rtx (*internal_arg_pointer) (void);
719 /* Return the diagnostic message string if conversion from FROMTYPE
720 to TOTYPE is not allowed, NULL otherwise. */
721 const char *(*invalid_conversion) (tree fromtype, tree totype);
723 /* Return the diagnostic message string if the unary operation OP is
724 not permitted on TYPE, NULL otherwise. */
725 const char *(*invalid_unary_op) (int op, tree type);
727 /* Return the diagnostic message string if the binary operation OP
728 is not permitted on TYPE1 and TYPE2, NULL otherwise. */
729 const char *(*invalid_binary_op) (int op, tree type1, tree type2);
731 /* Return the class for a secondary reload, and fill in extra information. */
732 enum reg_class (*secondary_reload) (bool, rtx, enum reg_class,
734 struct secondary_reload_info *);
736 /* Functions specific to the C++ frontend. */
738 /* Return the integer type used for guard variables. */
739 tree (*guard_type) (void);
740 /* Return true if only the low bit of the guard should be tested. */
741 bool (*guard_mask_bit) (void);
742 /* Returns the size of the array cookie for an array of type. */
743 tree (*get_cookie_size) (tree);
744 /* Returns true if the element size should be stored in the
746 bool (*cookie_has_size) (void);
747 /* Allows backends to perform additional processing when
748 deciding if a class should be exported or imported. */
749 int (*import_export_class) (tree, int);
750 /* Returns true if constructors and destructors return "this". */
751 bool (*cdtor_returns_this) (void);
752 /* Returns true if the key method for a class can be an inline
753 function, so long as it is not declared inline in the class
754 itself. Returning true is the behavior required by the Itanium
756 bool (*key_method_may_be_inline) (void);
757 /* DECL is a virtual table, virtual table table, typeinfo object,
758 or other similar implicit class data object that will be
759 emitted with external linkage in this translation unit. No ELF
760 visibility has been explicitly specified. If the target needs
761 to specify a visibility other than that of the containing class,
762 use this hook to set DECL_VISIBILITY and
763 DECL_VISIBILITY_SPECIFIED. */
764 void (*determine_class_data_visibility) (tree decl);
765 /* Returns true (the default) if virtual tables and other
766 similar implicit class data objects are always COMDAT if they
767 have external linkage. If this hook returns false, then
768 class data for classes whose virtual table will be emitted in
769 only one translation unit will not be COMDAT. */
770 bool (*class_data_always_comdat) (void);
771 /* Returns true if __aeabi_atexit should be used to register static
773 bool (*use_aeabi_atexit) (void);
774 /* TYPE is a C++ class (i.e., RECORD_TYPE or UNION_TYPE) that
775 has just been defined. Use this hook to make adjustments to the
776 class (eg, tweak visibility or perform any other required
777 target modifications). */
778 void (*adjust_class_at_definition) (tree type);
781 /* For targets that need to mark extra registers as live on entry to
782 the function, they should define this target hook and set their
783 bits in the bitmap passed in. */
784 void (*live_on_entry) (bitmap);
786 /* True if unwinding tables should be generated by default. */
787 bool unwind_tables_default;
789 /* Leave the boolean fields at the end. */
791 /* True if arbitrary sections are supported. */
792 bool have_named_sections;
794 /* True if we can create zeroed data by switching to a BSS section
795 and then using ASM_OUTPUT_SKIP to allocate the space. */
796 bool have_switchable_bss_sections;
798 /* True if "native" constructors and destructors are supported,
799 false if we're using collect2 for the job. */
800 bool have_ctors_dtors;
802 /* True if thread-local storage is supported. */
805 /* True if a small readonly data section is supported. */
806 bool have_srodata_section;
808 /* True if EH frame info sections should be zero-terminated. */
809 bool terminate_dw2_eh_frame_info;
811 /* True if #NO_APP should be emitted at the beginning of
813 bool file_start_app_off;
815 /* True if output_file_directive should be called for main_input_filename
816 at the beginning of assembly output. */
817 bool file_start_file_directive;
819 /* True if #pragma redefine_extname is to be supported. */
820 bool handle_pragma_redefine_extname;
822 /* True if #pragma extern_prefix is to be supported. */
823 bool handle_pragma_extern_prefix;
825 /* True if the target is allowed to reorder memory accesses unless
826 synchronization is explicitly requested. */
827 bool relaxed_ordering;
829 /* Returns true if we should generate exception tables for use with the
830 ARM EABI. The effects the encoding of function exception specifications.
832 bool arm_eabi_unwinder;
834 /* Leave the boolean fields at the end. */
837 extern struct gcc_target targetm;
839 #endif /* GCC_TARGET_H */