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