1 /* Data structure definitions for a generic GCC target.
2 Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
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 *);
71 /* Some places still assume that all pointer or address modes are the
72 standard Pmode and ptr_mode. These optimizations become invalid if
73 the target actually supports multiple different modes. For now,
74 we disable such optimizations on such targets, using this function. */
75 extern bool target_default_pointer_address_modes_p (void);
80 /* The struct used by the secondary_reload target hook. */
81 typedef struct secondary_reload_info
83 /* icode is actually an enum insn_code, but we don't want to force every
84 file that includes target.h to include optabs.h . */
86 int extra_cost; /* Cost for using (a) scratch register(s) to be taken
87 into account by copy_cost. */
88 /* The next two members are for the use of the backward
89 compatibility hook. */
90 struct secondary_reload_info *prev_sri;
91 int t_icode; /* Actually an enum insn_code - see above. */
92 } secondary_reload_info;
94 /* This is defined in sched-int.h . */
97 /* This is defined in ddg.h . */
100 /* Assembler instructions for creating various kinds of integer object. */
110 /* The target structure. This holds all the backend hooks. */
114 /* Functions that output assembler for the target. */
117 /* Opening and closing parentheses for asm expression grouping. */
118 const char *open_paren, *close_paren;
120 /* Assembler instructions for creating various kinds of integer object. */
122 struct asm_int_op aligned_op, unaligned_op;
124 /* Try to output the assembler code for an integer object whose
125 value is given by X. SIZE is the size of the object in bytes and
126 ALIGNED_P indicates whether it is aligned. Return true if
127 successful. Only handles cases for which BYTE_OP, ALIGNED_OP
128 and UNALIGNED_OP are NULL. */
129 bool (* integer) (rtx x, unsigned int size, int aligned_p);
131 /* Output code that will globalize a label. */
132 void (* globalize_label) (FILE *, const char *);
134 /* Output code that will globalize a declaration. */
135 void (* globalize_decl_name) (FILE *, tree);
137 /* Output code that will emit a label for unwind info, if this
138 target requires such labels. Second argument is the decl the
139 unwind info is associated with, third is a boolean: true if
140 this is for exception handling, fourth is a boolean: true if
141 this is only a placeholder for an omitted FDE. */
142 void (* unwind_label) (FILE *, tree, int, int);
144 /* Output code that will emit a label to divide up the exception
146 void (* except_table_label) (FILE *);
148 /* Emit any directives required to unwind this instruction. */
149 void (* unwind_emit) (FILE *, rtx);
151 /* Output an internal label. */
152 void (* internal_label) (FILE *, const char *, unsigned long);
154 /* Emit a ttype table reference to a typeinfo object. */
155 bool (* ttype) (rtx);
157 /* Emit an assembler directive to set visibility for the symbol
158 associated with the tree decl. */
159 void (* visibility) (tree, int);
161 /* Output the assembler code for entry to a function. */
162 void (* function_prologue) (FILE *, HOST_WIDE_INT);
164 /* Output the assembler code for end of prologue. */
165 void (* function_end_prologue) (FILE *);
167 /* Output the assembler code for start of epilogue. */
168 void (* function_begin_epilogue) (FILE *);
170 /* Output the assembler code for function exit. */
171 void (* function_epilogue) (FILE *, HOST_WIDE_INT);
173 /* Initialize target-specific sections. */
174 void (* init_sections) (void);
176 /* Tell assembler to change to section NAME with attributes FLAGS.
177 If DECL is non-NULL, it is the VAR_DECL or FUNCTION_DECL with
178 which this section is associated. */
179 void (* named_section) (const char *name, unsigned int flags, tree decl);
181 /* Return a mask describing how relocations should be treated when
182 selecting sections. Bit 1 should be set if global relocations
183 should be placed in a read-write section; bit 0 should be set if
184 local relocations should be placed in a read-write section. */
185 int (*reloc_rw_mask) (void);
187 /* Return a section for EXP. It may be a DECL or a constant. RELOC
188 is nonzero if runtime relocations must be applied; bit 1 will be
189 set if the runtime relocations require non-local name resolution.
190 ALIGN is the required alignment of the data. */
191 section *(* select_section) (tree, int, unsigned HOST_WIDE_INT);
193 /* Return a section for X. MODE is X's mode and ALIGN is its
194 alignment in bits. */
195 section *(* select_rtx_section) (enum machine_mode, rtx,
196 unsigned HOST_WIDE_INT);
198 /* Select a unique section name for DECL. RELOC is the same as
199 for SELECT_SECTION. */
200 void (* unique_section) (tree, int);
202 /* Return the readonly data section associated with function DECL. */
203 section *(* function_rodata_section) (tree);
205 /* Output a constructor for a symbol with a given priority. */
206 void (* constructor) (rtx, int);
208 /* Output a destructor for a symbol with a given priority. */
209 void (* destructor) (rtx, int);
211 /* Output the assembler code for a thunk function. THUNK_DECL is the
212 declaration for the thunk function itself, FUNCTION is the decl for
213 the target function. DELTA is an immediate constant offset to be
214 added to THIS. If VCALL_OFFSET is nonzero, the word at
215 *(*this + vcall_offset) should be added to THIS. */
216 void (* output_mi_thunk) (FILE *file, tree thunk_decl,
217 HOST_WIDE_INT delta, HOST_WIDE_INT vcall_offset,
220 /* Determine whether output_mi_thunk would succeed. */
221 /* ??? Ideally, this hook would not exist, and success or failure
222 would be returned from output_mi_thunk directly. But there's
223 too much undo-able setup involved in invoking output_mi_thunk.
224 Could be fixed by making output_mi_thunk emit rtl instead of
225 text to the output file. */
226 bool (* can_output_mi_thunk) (const_tree thunk_decl, HOST_WIDE_INT delta,
227 HOST_WIDE_INT vcall_offset,
228 const_tree function_decl);
230 /* Output any boilerplate text needed at the beginning of a
232 void (*file_start) (void);
234 /* Output any boilerplate text needed at the end of a
236 void (*file_end) (void);
238 /* Output an assembler pseudo-op to declare a library function name
240 void (*external_libcall) (rtx);
242 /* Output an assembler directive to mark decl live. This instructs
243 linker to not dead code strip this symbol. */
244 void (*mark_decl_preserved) (const char *);
246 /* Output a record of the command line switches that have been passed. */
247 print_switch_fn_type record_gcc_switches;
248 /* The name of the section that the example ELF implementation of
249 record_gcc_switches will use to store the information. Target
250 specific versions of record_gcc_switches may or may not use
252 const char * record_gcc_switches_section;
254 /* Output the definition of a section anchor. */
255 void (*output_anchor) (rtx);
257 /* Output a DTP-relative reference to a TLS symbol. */
258 void (*output_dwarf_dtprel) (FILE *file, int size, rtx x);
260 /* Some target machines need to postscan each insn after it is output. */
261 void (*final_postscan_insn) (FILE *, rtx, rtx *, int);
263 /* Emit the trampoline template. This hook may be NULL. */
264 void (*trampoline_template) (FILE *);
267 /* Functions relating to instruction scheduling. */
270 /* Given the current cost, COST, of an insn, INSN, calculate and
271 return a new cost based on its relationship to DEP_INSN through
272 the dependence LINK. The default is to make no adjustment. */
273 int (* adjust_cost) (rtx insn, rtx link, rtx dep_insn, int cost);
275 /* Adjust the priority of an insn as you see fit. Returns the new
277 int (* adjust_priority) (rtx, int);
279 /* Function which returns the maximum number of insns that can be
280 scheduled in the same machine cycle. This must be constant
281 over an entire compilation. The default is 1. */
282 int (* issue_rate) (void);
284 /* Calculate how much this insn affects how many more insns we
285 can emit this cycle. Default is they all cost the same. */
286 int (* variable_issue) (FILE *, int, rtx, int);
288 /* Initialize machine-dependent scheduling code. */
289 void (* md_init) (FILE *, int, int);
291 /* Finalize machine-dependent scheduling code. */
292 void (* md_finish) (FILE *, int);
294 /* Initialize machine-dependent function wide scheduling code. */
295 void (* md_init_global) (FILE *, int, int);
297 /* Finalize machine-dependent function wide scheduling code. */
298 void (* md_finish_global) (FILE *, int);
300 /* Reorder insns in a machine-dependent fashion, in two different
301 places. Default does nothing. */
302 int (* reorder) (FILE *, int, rtx *, int *, int);
303 int (* reorder2) (FILE *, int, rtx *, int *, int);
305 /* The following member value is a pointer to a function called
306 after evaluation forward dependencies of insns in chain given
307 by two parameter values (head and tail correspondingly). */
308 void (* dependencies_evaluation_hook) (rtx, rtx);
310 /* The values of the following four members are pointers to
311 functions used to simplify the automaton descriptions.
312 dfa_pre_cycle_insn and dfa_post_cycle_insn give functions
313 returning insns which are used to change the pipeline hazard
314 recognizer state when the new simulated processor cycle
315 correspondingly starts and finishes. The function defined by
316 init_dfa_pre_cycle_insn and init_dfa_post_cycle_insn are used
317 to initialize the corresponding insns. The default values of
318 the members result in not changing the automaton state when
319 the new simulated processor cycle correspondingly starts and
321 void (* init_dfa_pre_cycle_insn) (void);
322 rtx (* dfa_pre_cycle_insn) (void);
323 void (* init_dfa_post_cycle_insn) (void);
324 rtx (* dfa_post_cycle_insn) (void);
326 /* The values of the following two members are pointers to
327 functions used to simplify the automaton descriptions.
328 dfa_pre_advance_cycle and dfa_post_advance_cycle are getting called
329 immediately before and after cycle is advanced. */
330 void (* dfa_pre_advance_cycle) (void);
331 void (* dfa_post_advance_cycle) (void);
333 /* The following member value is a pointer to a function returning value
334 which defines how many insns in queue `ready' will we try for
335 multi-pass scheduling. If the member value is nonzero and the
336 function returns positive value, the DFA based scheduler will make
337 multi-pass scheduling for the first cycle. In other words, we will
338 try to choose ready insn which permits to start maximum number of
339 insns on the same cycle. */
340 int (* first_cycle_multipass_dfa_lookahead) (void);
342 /* The following member value is pointer to a function controlling
343 what insns from the ready insn queue will be considered for the
344 multipass insn scheduling. If the hook returns zero for insn
345 passed as the parameter, the insn will be not chosen to be
347 int (* first_cycle_multipass_dfa_lookahead_guard) (rtx);
349 /* The following member value is pointer to a function called by
350 the insn scheduler before issuing insn passed as the third
351 parameter on given cycle. If the hook returns nonzero, the
352 insn is not issued on given processors cycle. Instead of that,
353 the processor cycle is advanced. If the value passed through
354 the last parameter is zero, the insn ready queue is not sorted
355 on the new cycle start as usually. The first parameter passes
356 file for debugging output. The second one passes the scheduler
357 verbose level of the debugging output. The forth and the fifth
358 parameter values are correspondingly processor cycle on which
359 the previous insn has been issued and the current processor
361 int (* dfa_new_cycle) (FILE *, int, rtx, int, int, int *);
363 /* The following member value is a pointer to a function called by the
364 insn scheduler. It should return true if there exists a dependence
365 which is considered costly by the target, between the insn
366 DEP_PRO (&_DEP), and the insn DEP_CON (&_DEP). The first parameter is
367 the dep that represents the dependence between the two insns. The
368 second argument is the cost of the dependence as estimated by
369 the scheduler. The last argument is the distance in cycles
370 between the already scheduled insn (first parameter) and the
371 second insn (second parameter). */
372 bool (* is_costly_dependence) (struct _dep *_dep, int, int);
374 /* Given the current cost, COST, of an insn, INSN, calculate and
375 return a new cost based on its relationship to DEP_INSN through the
376 dependence of type DEP_TYPE. The default is to make no adjustment. */
377 int (* adjust_cost_2) (rtx insn, int, rtx dep_insn, int cost, int dw);
379 /* The following member value is a pointer to a function called
380 by the insn scheduler. This hook is called to notify the backend
381 that new instructions were emitted. */
382 void (* h_i_d_extended) (void);
384 /* Next 5 functions are for multi-point scheduling. */
386 /* Allocate memory for scheduler context. */
387 void *(* alloc_sched_context) (void);
389 /* Fills the context from the local machine scheduler context. */
390 void (* init_sched_context) (void *, bool);
392 /* Sets local machine scheduler context to a saved value. */
393 void (* set_sched_context) (void *);
395 /* Clears a scheduler context so it becomes like after init. */
396 void (* clear_sched_context) (void *);
398 /* Frees the scheduler context. */
399 void (* free_sched_context) (void *);
401 /* The following member value is a pointer to a function called
402 by the insn scheduler.
403 The first parameter is an instruction, the second parameter is the type
404 of the requested speculation, and the third parameter is a pointer to the
405 speculative pattern of the corresponding type (set if return value == 1).
407 -1, if there is no pattern, that will satisfy the requested speculation
409 0, if current pattern satisfies the requested speculation type,
410 1, if pattern of the instruction should be changed to the newly
412 int (* speculate_insn) (rtx, int, rtx *);
414 /* The following member value is a pointer to a function called
415 by the insn scheduler. It should return true if the check instruction
416 passed as the parameter needs a recovery block. */
417 bool (* needs_block_p) (int);
419 /* The following member value is a pointer to a function called
420 by the insn scheduler. It should return a pattern for the check
422 The first parameter is a speculative instruction, the second parameter
423 is the label of the corresponding recovery block (or null, if it is a
424 simple check). If the mutation of the check is requested (e.g. from
425 ld.c to chk.a), the third parameter is true - in this case the first
426 parameter is the previous check. */
427 rtx (* gen_spec_check) (rtx, rtx, int);
429 /* The following member value is a pointer to a function controlling
430 what insns from the ready insn queue will be considered for the
431 multipass insn scheduling. If the hook returns zero for the insn
432 passed as the parameter, the insn will not be chosen to be
433 issued. This hook is used to discard speculative instructions,
434 that stand at the first position of the ready list. */
435 bool (* first_cycle_multipass_dfa_lookahead_guard_spec) (const_rtx);
437 /* The following member value is a pointer to a function that provides
438 information about the speculation capabilities of the target.
439 The parameter is a pointer to spec_info variable. */
440 void (* set_sched_flags) (struct spec_info_def *);
442 /* Return speculation types of the instruction passed as the parameter. */
443 int (* get_insn_spec_ds) (rtx);
445 /* Return speculation types that are checked for the instruction passed as
447 int (* get_insn_checked_ds) (rtx);
449 /* Return bool if rtx scanning should just skip current layer and
450 advance to the inner rtxes. */
451 bool (* skip_rtx_p) (const_rtx);
453 /* The following member value is a pointer to a function that provides
454 information about the target resource-based lower bound which is
455 used by the swing modulo scheduler. The parameter is a pointer
457 int (* sms_res_mii) (struct ddg *);
460 /* Functions relating to vectorization. */
463 /* The following member value is a pointer to a function called
464 by the vectorizer, and return the decl of the target builtin
466 tree (* builtin_mask_for_load) (void);
468 /* Returns a code for builtin that realizes vectorized version of
469 function, or NULL_TREE if not available. */
470 tree (* builtin_vectorized_function) (unsigned, tree, tree);
472 /* Returns a code for builtin that realizes vectorized version of
473 conversion, or NULL_TREE if not available. */
474 tree (* builtin_conversion) (unsigned, tree);
476 /* Target builtin that implements vector widening multiplication.
477 builtin_mul_widen_eve computes the element-by-element products
478 for the even elements, and builtin_mul_widen_odd computes the
479 element-by-element products for the odd elements. */
480 tree (* builtin_mul_widen_even) (tree);
481 tree (* builtin_mul_widen_odd) (tree);
483 /* Returns the cost to be added to the overheads involved with
484 executing the vectorized version of a loop. */
485 int (*builtin_vectorization_cost) (bool);
487 /* Return true if vector alignment is reachable (by peeling N
488 iterations) for the given type. */
489 bool (* vector_alignment_reachable) (const_tree, bool);
491 /* Target builtin that implements vector permute. */
492 tree (* builtin_vec_perm) (tree, tree*);
494 /* Return true if a vector created for builtin_vec_perm is valid. */
495 bool (* builtin_vec_perm_ok) (tree, tree);
497 /* Return true if the target supports misaligned store/load of a
498 specific factor denoted in the third parameter. The last parameter
499 is true if the access is defined in a packed struct. */
500 bool (* builtin_support_vector_misalignment) (enum machine_mode,
501 const_tree, int, bool);
504 /* The initial value of target_flags. */
505 int default_target_flags;
507 /* Allow target specific overriding of option settings after options have
508 been changed by an attribute or pragma or when it is reset at the
509 end of the code affected by an attribute or pragma. */
510 void (* override_options_after_change) (void);
512 /* Handle target switch CODE (an OPT_* value). ARG is the argument
513 passed to the switch; it is NULL if no argument was. VALUE is the
514 value of ARG if CODE specifies a UInteger option, otherwise it is
515 1 if the positive form of the switch was used and 0 if the negative
516 form was. Return true if the switch was valid. */
517 bool (* handle_option) (size_t code, const char *arg, int value);
519 /* Display extra, target specific information in response to a
520 --target-help switch. */
521 void (* target_help) (void);
523 /* Return machine mode for filter value. */
524 enum machine_mode (* eh_return_filter_mode) (void);
526 /* Return machine mode for libgcc expanded cmp instructions. */
527 enum machine_mode (* libgcc_cmp_return_mode) (void);
529 /* Return machine mode for libgcc expanded shift instructions. */
530 enum machine_mode (* libgcc_shift_count_mode) (void);
532 /* Return machine mode to be used for _Unwind_Word type. */
533 enum machine_mode (* unwind_word_mode) (void);
535 /* Given two decls, merge their attributes and return the result. */
536 tree (* merge_decl_attributes) (tree, tree);
538 /* Given two types, merge their attributes and return the result. */
539 tree (* merge_type_attributes) (tree, tree);
541 /* Table of machine attributes and functions to handle them.
543 const struct attribute_spec *attribute_table;
545 /* Return zero if the attributes on TYPE1 and TYPE2 are incompatible,
546 one if they are compatible and two if they are nearly compatible
547 (which causes a warning to be generated). */
548 int (* comp_type_attributes) (const_tree type1, const_tree type2);
550 /* Assign default attributes to the newly defined TYPE. */
551 void (* set_default_type_attributes) (tree type);
553 /* Insert attributes on the newly created DECL. */
554 void (* insert_attributes) (tree decl, tree *attributes);
556 /* Return true if FNDECL (which has at least one machine attribute)
557 can be inlined despite its machine attributes, false otherwise. */
558 bool (* function_attribute_inlinable_p) (const_tree fndecl);
560 /* Return true if bitfields in RECORD_TYPE should follow the
561 Microsoft Visual C++ bitfield layout rules. */
562 bool (* ms_bitfield_layout_p) (const_tree record_type);
564 /* True if the target supports decimal floating point. */
565 bool (* decimal_float_supported_p) (void);
567 /* True if the target supports fixed-point. */
568 bool (* fixed_point_supported_p) (void);
570 /* Return true if anonymous bitfields affect structure alignment. */
571 bool (* align_anon_bitfield) (void);
573 /* Return true if volatile bitfields should use the narrowest type possible.
574 Return false if they should use the container type. */
575 bool (* narrow_volatile_bitfield) (void);
577 /* Set up target-specific built-in functions. */
578 void (* init_builtins) (void);
580 /* Initialize (if INITIALIZE_P is true) and return the target-specific
581 built-in function decl for CODE.
582 Return NULL if that is not possible. Return error_mark_node if CODE
583 is outside of the range of valid target builtin function codes. */
584 tree (* builtin_decl) (unsigned code, bool initialize_p);
586 /* Expand a target-specific builtin. */
587 rtx (* expand_builtin) (tree exp, rtx target, rtx subtarget,
588 enum machine_mode mode, int ignore);
590 /* Select a replacement for a target-specific builtin. This is done
591 *before* regular type checking, and so allows the target to
592 implement a crude form of function overloading. The result is a
593 complete expression that implements the operation. PARAMS really
594 has type VEC(tree,gc)*, but we don't want to include tree.h
596 tree (*resolve_overloaded_builtin) (unsigned int /*location_t*/,
597 tree decl, void *params);
599 /* Fold a target-specific builtin. */
600 tree (* fold_builtin) (tree fndecl, tree arglist, bool ignore);
602 /* Returns a code for a target-specific builtin that implements
603 reciprocal of the function, or NULL_TREE if not available. */
604 tree (* builtin_reciprocal) (unsigned, bool, bool);
606 /* For a vendor-specific TYPE, return a pointer to a statically-allocated
607 string containing the C++ mangling for TYPE. In all other cases, return
609 const char * (* mangle_type) (const_tree type);
611 /* Make any adjustments to libfunc names needed for this target. */
612 void (* init_libfuncs) (void);
614 /* Given a decl, a section name, and whether the decl initializer
615 has relocs, choose attributes for the section. */
616 /* ??? Should be merged with SELECT_SECTION and UNIQUE_SECTION. */
617 unsigned int (* section_type_flags) (tree, const char *, int);
619 /* True if new jumps cannot be created, to replace existing ones or
620 not, at the current point in the compilation. */
621 bool (* cannot_modify_jumps_p) (void);
623 /* Return a register class for which branch target register
624 optimizations should be applied. */
625 enum reg_class (* branch_target_register_class) (void);
627 /* Return true if branch target register optimizations should include
628 callee-saved registers that are not already live during the current
629 function. AFTER_PE_GEN is true if prologues and epilogues have
630 already been generated. */
631 bool (* branch_target_register_callee_saved) (bool after_pe_gen);
633 /* Return true if the target supports conditional execution. */
634 bool (* have_conditional_execution) (void);
636 /* True if the constant X cannot be placed in the constant pool. */
637 bool (* cannot_force_const_mem) (rtx);
639 /* True if the insn X cannot be duplicated. */
640 bool (* cannot_copy_insn_p) (rtx);
642 /* True if X is considered to be commutative. */
643 bool (* commutative_p) (const_rtx, int);
645 /* Given an invalid address X for a given machine mode, try machine-specific
646 ways to make it legitimate. Return X or an invalid address on failure. */
647 rtx (* legitimize_address) (rtx, rtx, enum machine_mode);
649 /* Given an address RTX, undo the effects of LEGITIMIZE_ADDRESS. */
650 rtx (* delegitimize_address) (rtx);
652 /* Given an address RTX, say whether it is valid. */
653 bool (* legitimate_address_p) (enum machine_mode, rtx, bool);
655 /* True if the given constant can be put into an object_block. */
656 bool (* use_blocks_for_constant_p) (enum machine_mode, const_rtx);
658 /* The minimum and maximum byte offsets for anchored addresses. */
659 HOST_WIDE_INT min_anchor_offset;
660 HOST_WIDE_INT max_anchor_offset;
662 /* True if section anchors can be used to access the given symbol. */
663 bool (* use_anchors_for_symbol_p) (const_rtx);
665 /* True if it is OK to do sibling call optimization for the specified
666 call expression EXP. DECL will be the called function, or NULL if
667 this is an indirect call. */
668 bool (*function_ok_for_sibcall) (tree decl, tree exp);
670 /* Establish appropriate back-end context for processing the function
671 FNDECL. The argument might be NULL to indicate processing at top
672 level, outside of any function scope. */
673 void (*set_current_function) (tree fndecl);
675 /* True if EXP should be placed in a "small data" section. */
676 bool (* in_small_data_p) (const_tree);
678 /* True if EXP names an object for which name resolution must resolve
679 to the current executable or shared library. */
680 bool (* binds_local_p) (const_tree);
682 /* Modify and return the identifier of a DECL's external name,
683 originally identified by ID, as required by the target,
684 (eg, append @nn to windows32 stdcall function names).
685 The default is to return ID without modification. */
686 tree (* mangle_decl_assembler_name) (tree decl, tree id);
688 /* Do something target-specific to record properties of the DECL into
689 the associated SYMBOL_REF. */
690 void (* encode_section_info) (tree, rtx, int);
692 /* Undo the effects of encode_section_info on the symbol string. */
693 const char * (* strip_name_encoding) (const char *);
695 /* If shift optabs for MODE are known to always truncate the shift count,
696 return the mask that they apply. Return 0 otherwise. */
697 unsigned HOST_WIDE_INT (* shift_truncation_mask) (enum machine_mode mode);
699 /* Return the number of divisions in the given MODE that should be present,
700 so that it is profitable to turn the division into a multiplication by
702 unsigned int (* min_divisions_for_recip_mul) (enum machine_mode mode);
704 /* If the representation of integral MODE is such that values are
705 always sign-extended to a wider mode MODE_REP then return
706 SIGN_EXTEND. Return UNKNOWN otherwise. */
707 /* Note that the return type ought to be RTX_CODE, but that's not
708 necessarily defined at this point. */
709 int (* mode_rep_extended) (enum machine_mode mode,
710 enum machine_mode mode_rep);
712 /* True if MODE is valid for a pointer in __attribute__((mode("MODE"))). */
713 bool (* valid_pointer_mode) (enum machine_mode mode);
715 /* Support for named address spaces. */
717 /* MODE to use for a pointer into another address space. */
718 enum machine_mode (* pointer_mode) (addr_space_t);
720 /* MODE to use for an address in another address space. */
721 enum machine_mode (* address_mode) (addr_space_t);
723 /* True if MODE is valid for a pointer in __attribute__((mode("MODE")))
724 in another address space. */
725 bool (* valid_pointer_mode) (enum machine_mode, addr_space_t);
727 /* True if an address is a valid memory address to a given named address
728 space for a given mode. */
729 bool (* legitimate_address_p) (enum machine_mode, rtx, bool, addr_space_t);
731 /* Return an updated address to convert an invalid pointer to a named
732 address space to a valid one. If NULL_RTX is returned use machine
733 independent methods to make the address valid. */
734 rtx (* legitimize_address) (rtx, rtx, enum machine_mode, addr_space_t);
736 /* True if one named address space is a subset of another named address. */
737 bool (* subset_p) (addr_space_t, addr_space_t);
739 /* Function to convert an rtl expression from one address space to
741 rtx (* convert) (rtx, tree, tree);
745 /* True if MODE is valid for the target. By "valid", we mean able to
746 be manipulated in non-trivial ways. In particular, this means all
747 the arithmetic is supported. */
748 bool (* scalar_mode_supported_p) (enum machine_mode mode);
750 /* Similarly for vector modes. "Supported" here is less strict. At
751 least some operations are supported; need to check optabs or builtins
752 for further details. */
753 bool (* vector_mode_supported_p) (enum machine_mode mode);
755 /* Compute a (partial) cost for rtx X. Return true if the complete
756 cost has been computed, and false if subexpressions should be
757 scanned. In either case, *TOTAL contains the cost result. */
758 /* Note that CODE and OUTER_CODE ought to be RTX_CODE, but that's
759 not necessarily defined at this point. */
760 bool (* rtx_costs) (rtx x, int code, int outer_code, int *total, bool speed);
762 /* Compute the cost of X, used as an address. Never called with
763 invalid addresses. */
764 int (* address_cost) (rtx x, bool speed);
766 /* Return where to allocate pseudo for a given hard register initial
768 rtx (* allocate_initial_value) (rtx x);
770 /* Return nonzero if evaluating UNSPEC[_VOLATILE] X might cause a trap.
771 FLAGS has the same meaning as in rtlanal.c: may_trap_p_1. */
772 int (* unspec_may_trap_p) (const_rtx x, unsigned flags);
774 /* Given a register, this hook should return a parallel of registers
775 to represent where to find the register pieces. Define this hook
776 if the register and its mode are represented in Dwarf in
777 non-contiguous locations, or if the register should be
778 represented in more than one register in Dwarf. Otherwise, this
779 hook should return NULL_RTX. */
780 rtx (* dwarf_register_span) (rtx);
782 /* If expand_builtin_init_dwarf_reg_sizes needs to fill in table
783 entries not corresponding directly to registers below
784 FIRST_PSEUDO_REGISTER, this hook should generate the necessary
785 code, given the address of the table. */
786 void (* init_dwarf_reg_sizes_extra) (tree);
788 /* Fetch the fixed register(s) which hold condition codes, for
789 targets where it makes sense to look for duplicate assignments to
790 the condition codes. This should return true if there is such a
791 register, false otherwise. The arguments should be set to the
792 fixed register numbers. Up to two condition code registers are
793 supported. If there is only one for this target, the int pointed
794 at by the second argument should be set to -1. */
795 bool (* fixed_condition_code_regs) (unsigned int *, unsigned int *);
797 /* If two condition code modes are compatible, return a condition
798 code mode which is compatible with both, such that a comparison
799 done in the returned mode will work for both of the original
800 modes. If the condition code modes are not compatible, return
802 enum machine_mode (* cc_modes_compatible) (enum machine_mode,
805 /* Do machine-dependent code transformations. Called just before
806 delayed-branch scheduling. */
807 void (* machine_dependent_reorg) (void);
809 /* Create the __builtin_va_list type. */
810 tree (* build_builtin_va_list) (void);
812 /* Get the cfun/fndecl calling abi __builtin_va_list type. */
813 tree (* fn_abi_va_list) (tree);
815 /* Get the __builtin_va_list type dependent on input type. */
816 tree (* canonical_va_list_type) (tree);
818 /* Expand the __builtin_va_start builtin. */
819 void (* expand_builtin_va_start) (tree valist, rtx nextarg);
821 /* Gimplifies a VA_ARG_EXPR. */
822 tree (* gimplify_va_arg_expr) (tree valist, tree type, gimple_seq *pre_p,
825 /* Validity-checking routines for PCH files, target-specific.
826 get_pch_validity returns a pointer to the data to be stored,
827 and stores the size in its argument. pch_valid_p gets the same
828 information back and returns NULL if the PCH is valid,
829 or an error message if not.
831 void * (* get_pch_validity) (size_t *);
832 const char * (* pch_valid_p) (const void *, size_t);
834 /* If nonnull, this function checks whether a PCH file with the
835 given set of target flags can be used. It returns NULL if so,
836 otherwise it returns an error message. */
837 const char *(*check_pch_target_flags) (int);
839 /* True if the compiler should give an enum type only as many
840 bytes as it takes to represent the range of possible values of
842 bool (* default_short_enums) (void);
844 /* This target hook returns an rtx that is used to store the address
845 of the current frame into the built-in setjmp buffer. */
846 rtx (* builtin_setjmp_frame_value) (void);
848 /* This target hook should add STRING_CST trees for any hard regs
849 the port wishes to automatically clobber for an asm. */
850 tree (* md_asm_clobbers) (tree, tree, tree);
852 /* This target hook allows the backend to specify a calling convention
853 in the debug information. This function actually returns an
854 enum dwarf_calling_convention, but because of forward declarations
855 and not wanting to include dwarf2.h everywhere target.h is included
856 the function is being declared as an int. */
857 int (* dwarf_calling_convention) (const_tree);
859 /* This target hook allows the backend to emit frame-related insns that
860 contain UNSPECs or UNSPEC_VOLATILEs. The call frame debugging info
861 engine will invoke it on insns of the form
862 (set (reg) (unspec [...] UNSPEC_INDEX))
864 (set (reg) (unspec_volatile [...] UNSPECV_INDEX))
865 to let the backend emit the call frame instructions. */
866 void (* dwarf_handle_frame_unspec) (const char *, rtx, int);
868 /* Perform architecture specific checking of statements gimplified
869 from VA_ARG_EXPR. STMT is the statement. Returns true if the statement
870 doesn't need to be checked for va_list references. */
871 bool (* stdarg_optimize_hook) (struct stdarg_info *ai, const_gimple stmt);
873 /* This target hook allows the operating system to override the DECL
874 that represents the external variable that contains the stack
875 protection guard variable. The type of this DECL is ptr_type_node. */
876 tree (* stack_protect_guard) (void);
878 /* This target hook allows the operating system to override the CALL_EXPR
879 that is invoked when a check vs the guard variable fails. */
880 tree (* stack_protect_fail) (void);
882 /* Returns NULL if target supports the insn within a doloop block,
883 otherwise it returns an error message. */
884 const char * (*invalid_within_doloop) (const_rtx);
886 /* DECL is a variable or function with __attribute__((dllimport))
887 specified. Use this hook if the target needs to add extra validation
888 checks to handle_dll_attribute (). */
889 bool (* valid_dllimport_attribute_p) (const_tree decl);
891 /* If non-zero, align constant anchors in CSE to a multiple of this
893 unsigned HOST_WIDE_INT const_anchor;
895 /* Functions relating to calls - argument passing, returns, etc. */
897 enum machine_mode (*promote_function_mode) (const_tree type,
898 enum machine_mode mode,
902 bool (*promote_prototypes) (const_tree fntype);
903 rtx (*struct_value_rtx) (tree fndecl, int incoming);
904 bool (*return_in_memory) (const_tree type, const_tree fndecl);
905 bool (*return_in_msb) (const_tree type);
907 /* Return true if a parameter must be passed by reference. TYPE may
908 be null if this is a libcall. CA may be null if this query is
909 from __builtin_va_arg. */
910 bool (*pass_by_reference) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
911 const_tree type, bool named_arg);
913 rtx (*expand_builtin_saveregs) (void);
914 /* Returns pretend_argument_size. */
915 void (*setup_incoming_varargs) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
916 tree type, int *pretend_arg_size,
918 bool (*strict_argument_naming) (CUMULATIVE_ARGS *ca);
919 /* Returns true if we should use
920 targetm.calls.setup_incoming_varargs() and/or
921 targetm.calls.strict_argument_naming(). */
922 bool (*pretend_outgoing_varargs_named) (CUMULATIVE_ARGS *ca);
924 /* Given a complex type T, return true if a parameter of type T
925 should be passed as two scalars. */
926 bool (* split_complex_arg) (const_tree type);
928 /* Return true if type T, mode MODE, may not be passed in registers,
929 but must be passed on the stack. */
930 /* ??? This predicate should be applied strictly after pass-by-reference.
931 Need audit to verify that this is the case. */
932 bool (* must_pass_in_stack) (enum machine_mode mode, const_tree t);
934 /* Return true if type TYPE, mode MODE, which is passed by reference,
935 should have the object copy generated by the callee rather than
936 the caller. It is never called for TYPE requiring constructors. */
937 bool (* callee_copies) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
938 const_tree type, bool named);
940 /* Return zero for arguments passed entirely on the stack or entirely
941 in registers. If passed in both, return the number of bytes passed
942 in registers; the balance is therefore passed on the stack. */
943 int (* arg_partial_bytes) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
944 tree type, bool named);
946 /* Return the diagnostic message string if function without a prototype
947 is not allowed for this 'val' argument; NULL otherwise. */
948 const char *(*invalid_arg_for_unprototyped_fn) (const_tree typelist,
952 /* Return an rtx for the return value location of the function
953 specified by FN_DECL_OR_TYPE with a return type of RET_TYPE. */
954 rtx (*function_value) (const_tree ret_type, const_tree fn_decl_or_type,
957 /* Return the rtx for the result of a libcall of mode MODE,
958 calling the function FN_NAME. */
959 rtx (*libcall_value) (enum machine_mode, const_rtx);
961 /* Return an rtx for the argument pointer incoming to the
963 rtx (*internal_arg_pointer) (void);
965 /* Update the current function stack boundary if needed. */
966 void (*update_stack_boundary) (void);
968 /* Handle stack alignment and return an rtx for Dynamic Realign
969 Argument Pointer if necessary. */
970 rtx (*get_drap_rtx) (void);
972 /* Return true if all function parameters should be spilled to the
974 bool (*allocate_stack_slots_for_args) (void);
976 /* Return an rtx for the static chain for FNDECL. If INCOMING_P is true,
977 then it should be for the callee; otherwise for the caller. */
978 rtx (*static_chain) (const_tree fndecl, bool incoming_p);
980 /* Fill in the trampoline at MEM with a call to FNDECL and a
981 static chain value of CHAIN. */
982 void (*trampoline_init) (rtx mem, tree fndecl, rtx chain);
984 /* Adjust the address of the trampoline in a target-specific way. */
985 rtx (*trampoline_adjust_address) (rtx addr);
988 /* Return the diagnostic message string if conversion from FROMTYPE
989 to TOTYPE is not allowed, NULL otherwise. */
990 const char *(*invalid_conversion) (const_tree fromtype, const_tree totype);
992 /* Return the diagnostic message string if the unary operation OP is
993 not permitted on TYPE, NULL otherwise. */
994 const char *(*invalid_unary_op) (int op, const_tree type);
996 /* Return the diagnostic message string if the binary operation OP
997 is not permitted on TYPE1 and TYPE2, NULL otherwise. */
998 const char *(*invalid_binary_op) (int op, const_tree type1, const_tree type2);
1000 /* Return the diagnostic message string if TYPE is not valid as a
1001 function parameter type, NULL otherwise. */
1002 const char *(*invalid_parameter_type) (const_tree type);
1004 /* Return the diagnostic message string if TYPE is not valid as a
1005 function return type, NULL otherwise. */
1006 const char *(*invalid_return_type) (const_tree type);
1008 /* If values of TYPE are promoted to some other type when used in
1009 expressions (analogous to the integer promotions), return that type,
1010 or NULL_TREE otherwise. */
1011 tree (*promoted_type) (const_tree type);
1013 /* Convert EXPR to TYPE, if target-specific types with special conversion
1014 rules are involved. Return the converted expression, or NULL to apply
1015 the standard conversion rules. */
1016 tree (*convert_to_type) (tree type, tree expr);
1018 /* Return the array of IRA cover classes for the current target. */
1019 const enum reg_class *(*ira_cover_classes) (void);
1021 /* Return the class for a secondary reload, and fill in extra information. */
1022 enum reg_class (*secondary_reload) (bool, rtx, enum reg_class,
1024 secondary_reload_info *);
1026 /* This target hook allows the backend to perform additional
1027 processing while initializing for variable expansion. */
1028 void (* expand_to_rtl_hook) (void);
1030 /* This target hook allows the backend to perform additional
1031 instantiations on rtx that are not actually in insns yet,
1032 but will be later. */
1033 void (* instantiate_decls) (void);
1035 /* Return true if is OK to use a hard register REGNO as scratch register
1037 bool (* hard_regno_scratch_ok) (unsigned int regno);
1039 /* Return the smallest number of different values for which it is best to
1040 use a jump-table instead of a tree of conditional branches. */
1041 unsigned int (* case_values_threshold) (void);
1043 /* Retutn true if a function must have and use a frame pointer. */
1044 bool (* frame_pointer_required) (void);
1046 /* Returns true if the compiler is allowed to try to replace register number
1047 from-reg with register number to-reg. */
1048 bool (* can_eliminate) (const int, const int);
1050 /* Functions specific to the C family of frontends. */
1052 /* Return machine mode for non-standard suffix
1053 or VOIDmode if non-standard suffixes are unsupported. */
1054 enum machine_mode (*mode_for_suffix) (char);
1057 /* Functions specific to the C++ frontend. */
1059 /* Return the integer type used for guard variables. */
1060 tree (*guard_type) (void);
1061 /* Return true if only the low bit of the guard should be tested. */
1062 bool (*guard_mask_bit) (void);
1063 /* Returns the size of the array cookie for an array of type. */
1064 tree (*get_cookie_size) (tree);
1065 /* Returns true if the element size should be stored in the
1067 bool (*cookie_has_size) (void);
1068 /* Allows backends to perform additional processing when
1069 deciding if a class should be exported or imported. */
1070 int (*import_export_class) (tree, int);
1071 /* Returns true if constructors and destructors return "this". */
1072 bool (*cdtor_returns_this) (void);
1073 /* Returns true if the key method for a class can be an inline
1074 function, so long as it is not declared inline in the class
1075 itself. Returning true is the behavior required by the Itanium
1077 bool (*key_method_may_be_inline) (void);
1078 /* DECL is a virtual table, virtual table table, typeinfo object,
1079 or other similar implicit class data object that will be
1080 emitted with external linkage in this translation unit. No ELF
1081 visibility has been explicitly specified. If the target needs
1082 to specify a visibility other than that of the containing class,
1083 use this hook to set DECL_VISIBILITY and
1084 DECL_VISIBILITY_SPECIFIED. */
1085 void (*determine_class_data_visibility) (tree decl);
1086 /* Returns true (the default) if virtual tables and other
1087 similar implicit class data objects are always COMDAT if they
1088 have external linkage. If this hook returns false, then
1089 class data for classes whose virtual table will be emitted in
1090 only one translation unit will not be COMDAT. */
1091 bool (*class_data_always_comdat) (void);
1092 /* Returns true (the default) if the RTTI for the basic types,
1093 which is always defined in the C++ runtime, should be COMDAT;
1094 false if it should not be COMDAT. */
1095 bool (*library_rtti_comdat) (void);
1096 /* Returns true if __aeabi_atexit should be used to register static
1098 bool (*use_aeabi_atexit) (void);
1099 /* Returns true if target may use atexit in the same manner as
1100 __cxa_atexit to register static destructors. */
1101 bool (*use_atexit_for_cxa_atexit) (void);
1102 /* TYPE is a C++ class (i.e., RECORD_TYPE or UNION_TYPE) that
1103 has just been defined. Use this hook to make adjustments to the
1104 class (eg, tweak visibility or perform any other required
1105 target modifications). */
1106 void (*adjust_class_at_definition) (tree type);
1109 /* Functions and data for emulated TLS support. */
1111 /* Name of the address and common functions. */
1112 const char *get_address;
1113 const char *register_common;
1115 /* Prefixes for proxy variable and template. */
1116 const char *var_section;
1117 const char *tmpl_section;
1119 /* Prefixes for proxy variable and template. */
1120 const char *var_prefix;
1121 const char *tmpl_prefix;
1123 /* Function to generate field definitions of the proxy variable. */
1124 tree (*var_fields) (tree, tree *);
1126 /* Function to initialize a proxy variable. */
1127 tree (*var_init) (tree, tree, tree);
1129 /* Whether we are allowed to alter the usual alignment of the
1131 bool var_align_fixed;
1133 /* Whether we can emit debug information for TLS vars. */
1134 bool debug_form_tls_address;
1137 struct target_option_hooks {
1138 /* Function to validate the attribute((option(...))) strings or NULL. If
1139 the option is validated, it is assumed that DECL_FUNCTION_SPECIFIC will
1140 be filled in in the function decl node. */
1141 bool (*valid_attribute_p) (tree, tree, tree, int);
1143 /* Function to save any extra target state in the target options
1145 void (*save) (struct cl_target_option *);
1147 /* Function to restore any extra target state from the target options
1149 void (*restore) (struct cl_target_option *);
1151 /* Function to print any extra target state from the target options
1153 void (*print) (FILE *, int, struct cl_target_option *);
1155 /* Function to parse arguments to be validated for #pragma option, and to
1156 change the state if the options are valid. If the first argument is
1157 NULL, the second argument specifies the default options to use. Return
1158 true if the options are valid, and set the current state. */
1159 bool (*pragma_parse) (tree, tree);
1161 /* Function to determine if one function can inline another function. */
1162 bool (*can_inline_p) (tree, tree);
1165 /* For targets that need to mark extra registers as live on entry to
1166 the function, they should define this target hook and set their
1167 bits in the bitmap passed in. */
1168 void (*live_on_entry) (bitmap);
1170 /* True if unwinding tables should be generated by default. */
1171 bool unwind_tables_default;
1173 /* Leave the boolean fields at the end. */
1175 /* True if arbitrary sections are supported. */
1176 bool have_named_sections;
1178 /* True if we can create zeroed data by switching to a BSS section
1179 and then using ASM_OUTPUT_SKIP to allocate the space. */
1180 bool have_switchable_bss_sections;
1182 /* True if "native" constructors and destructors are supported,
1183 false if we're using collect2 for the job. */
1184 bool have_ctors_dtors;
1186 /* True if thread-local storage is supported. */
1189 /* True if a small readonly data section is supported. */
1190 bool have_srodata_section;
1192 /* True if EH frame info sections should be zero-terminated. */
1193 bool terminate_dw2_eh_frame_info;
1195 /* True if #NO_APP should be emitted at the beginning of
1197 bool file_start_app_off;
1199 /* True if output_file_directive should be called for main_input_filename
1200 at the beginning of assembly output. */
1201 bool file_start_file_directive;
1203 /* True if #pragma extern_prefix is to be supported. */
1204 bool handle_pragma_extern_prefix;
1206 /* True if the target is allowed to reorder memory accesses unless
1207 synchronization is explicitly requested. */
1208 bool relaxed_ordering;
1210 /* Returns true if we should generate exception tables for use with the
1211 ARM EABI. The effects the encoding of function exception specifications.
1213 bool arm_eabi_unwinder;
1215 /* Leave the boolean fields at the end. */
1218 extern struct gcc_target targetm;
1220 struct gcc_targetcm {
1221 /* Handle target switch CODE (an OPT_* value). ARG is the argument
1222 passed to the switch; it is NULL if no argument was. VALUE is the
1223 value of ARG if CODE specifies a UInteger option, otherwise it is
1224 1 if the positive form of the switch was used and 0 if the negative
1225 form was. Return true if the switch was valid. */
1226 bool (*handle_c_option) (size_t code, const char *arg, int value);
1229 /* Each target can provide their own. */
1230 extern struct gcc_targetcm targetcm;
1232 #endif /* GCC_TARGET_H */
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