1 /* Data structure definitions for a generic GCC target.
2 Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
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 any boilerplace text needed at the end of a
239 translation unit before debug and unwind info is emitted. */
240 void (*code_end) (void);
242 /* Output an assembler pseudo-op to declare a library function name
244 void (*external_libcall) (rtx);
246 /* Output an assembler directive to mark decl live. This instructs
247 linker to not dead code strip this symbol. */
248 void (*mark_decl_preserved) (const char *);
250 /* Output a record of the command line switches that have been passed. */
251 print_switch_fn_type record_gcc_switches;
252 /* The name of the section that the example ELF implementation of
253 record_gcc_switches will use to store the information. Target
254 specific versions of record_gcc_switches may or may not use
256 const char * record_gcc_switches_section;
258 /* Output the definition of a section anchor. */
259 void (*output_anchor) (rtx);
261 /* Output a DTP-relative reference to a TLS symbol. */
262 void (*output_dwarf_dtprel) (FILE *file, int size, rtx x);
264 /* Some target machines need to postscan each insn after it is output. */
265 void (*final_postscan_insn) (FILE *, rtx, rtx *, int);
267 /* Emit the trampoline template. This hook may be NULL. */
268 void (*trampoline_template) (FILE *);
271 /* Functions relating to instruction scheduling. */
274 /* Given the current cost, COST, of an insn, INSN, calculate and
275 return a new cost based on its relationship to DEP_INSN through
276 the dependence LINK. The default is to make no adjustment. */
277 int (* adjust_cost) (rtx insn, rtx link, rtx dep_insn, int cost);
279 /* Adjust the priority of an insn as you see fit. Returns the new
281 int (* adjust_priority) (rtx, int);
283 /* Function which returns the maximum number of insns that can be
284 scheduled in the same machine cycle. This must be constant
285 over an entire compilation. The default is 1. */
286 int (* issue_rate) (void);
288 /* Calculate how much this insn affects how many more insns we
289 can emit this cycle. Default is they all cost the same. */
290 int (* variable_issue) (FILE *, int, rtx, int);
292 /* Initialize machine-dependent scheduling code. */
293 void (* md_init) (FILE *, int, int);
295 /* Finalize machine-dependent scheduling code. */
296 void (* md_finish) (FILE *, int);
298 /* Initialize machine-dependent function wide scheduling code. */
299 void (* md_init_global) (FILE *, int, int);
301 /* Finalize machine-dependent function wide scheduling code. */
302 void (* md_finish_global) (FILE *, int);
304 /* Reorder insns in a machine-dependent fashion, in two different
305 places. Default does nothing. */
306 int (* reorder) (FILE *, int, rtx *, int *, int);
307 int (* reorder2) (FILE *, int, rtx *, int *, int);
309 /* The following member value is a pointer to a function called
310 after evaluation forward dependencies of insns in chain given
311 by two parameter values (head and tail correspondingly). */
312 void (* dependencies_evaluation_hook) (rtx, rtx);
314 /* The values of the following four members are pointers to
315 functions used to simplify the automaton descriptions.
316 dfa_pre_cycle_insn and dfa_post_cycle_insn give functions
317 returning insns which are used to change the pipeline hazard
318 recognizer state when the new simulated processor cycle
319 correspondingly starts and finishes. The function defined by
320 init_dfa_pre_cycle_insn and init_dfa_post_cycle_insn are used
321 to initialize the corresponding insns. The default values of
322 the members result in not changing the automaton state when
323 the new simulated processor cycle correspondingly starts and
325 void (* init_dfa_pre_cycle_insn) (void);
326 rtx (* dfa_pre_cycle_insn) (void);
327 void (* init_dfa_post_cycle_insn) (void);
328 rtx (* dfa_post_cycle_insn) (void);
330 /* The values of the following two members are pointers to
331 functions used to simplify the automaton descriptions.
332 dfa_pre_advance_cycle and dfa_post_advance_cycle are getting called
333 immediately before and after cycle is advanced. */
334 void (* dfa_pre_advance_cycle) (void);
335 void (* dfa_post_advance_cycle) (void);
337 /* The following member value is a pointer to a function returning value
338 which defines how many insns in queue `ready' will we try for
339 multi-pass scheduling. If the member value is nonzero and the
340 function returns positive value, the DFA based scheduler will make
341 multi-pass scheduling for the first cycle. In other words, we will
342 try to choose ready insn which permits to start maximum number of
343 insns on the same cycle. */
344 int (* first_cycle_multipass_dfa_lookahead) (void);
346 /* The following member value is pointer to a function controlling
347 what insns from the ready insn queue will be considered for the
348 multipass insn scheduling. If the hook returns zero for insn
349 passed as the parameter, the insn will be not chosen to be
351 int (* first_cycle_multipass_dfa_lookahead_guard) (rtx);
353 /* The following member value is pointer to a function called by
354 the insn scheduler before issuing insn passed as the third
355 parameter on given cycle. If the hook returns nonzero, the
356 insn is not issued on given processors cycle. Instead of that,
357 the processor cycle is advanced. If the value passed through
358 the last parameter is zero, the insn ready queue is not sorted
359 on the new cycle start as usually. The first parameter passes
360 file for debugging output. The second one passes the scheduler
361 verbose level of the debugging output. The forth and the fifth
362 parameter values are correspondingly processor cycle on which
363 the previous insn has been issued and the current processor
365 int (* dfa_new_cycle) (FILE *, int, rtx, int, int, int *);
367 /* The following member value is a pointer to a function called by the
368 insn scheduler. It should return true if there exists a dependence
369 which is considered costly by the target, between the insn
370 DEP_PRO (&_DEP), and the insn DEP_CON (&_DEP). The first parameter is
371 the dep that represents the dependence between the two insns. The
372 second argument is the cost of the dependence as estimated by
373 the scheduler. The last argument is the distance in cycles
374 between the already scheduled insn (first parameter) and the
375 second insn (second parameter). */
376 bool (* is_costly_dependence) (struct _dep *_dep, int, int);
378 /* Given the current cost, COST, of an insn, INSN, calculate and
379 return a new cost based on its relationship to DEP_INSN through the
380 dependence of type DEP_TYPE. The default is to make no adjustment. */
381 int (* adjust_cost_2) (rtx insn, int, rtx dep_insn, int cost, int dw);
383 /* The following member value is a pointer to a function called
384 by the insn scheduler. This hook is called to notify the backend
385 that new instructions were emitted. */
386 void (* h_i_d_extended) (void);
388 /* Next 5 functions are for multi-point scheduling. */
390 /* Allocate memory for scheduler context. */
391 void *(* alloc_sched_context) (void);
393 /* Fills the context from the local machine scheduler context. */
394 void (* init_sched_context) (void *, bool);
396 /* Sets local machine scheduler context to a saved value. */
397 void (* set_sched_context) (void *);
399 /* Clears a scheduler context so it becomes like after init. */
400 void (* clear_sched_context) (void *);
402 /* Frees the scheduler context. */
403 void (* free_sched_context) (void *);
405 /* The following member value is a pointer to a function called
406 by the insn scheduler.
407 The first parameter is an instruction, the second parameter is the type
408 of the requested speculation, and the third parameter is a pointer to the
409 speculative pattern of the corresponding type (set if return value == 1).
411 -1, if there is no pattern, that will satisfy the requested speculation
413 0, if current pattern satisfies the requested speculation type,
414 1, if pattern of the instruction should be changed to the newly
416 int (* speculate_insn) (rtx, int, rtx *);
418 /* The following member value is a pointer to a function called
419 by the insn scheduler. It should return true if the check instruction
420 passed as the parameter needs a recovery block. */
421 bool (* needs_block_p) (int);
423 /* The following member value is a pointer to a function called
424 by the insn scheduler. It should return a pattern for the check
426 The first parameter is a speculative instruction, the second parameter
427 is the label of the corresponding recovery block (or null, if it is a
428 simple check). If the mutation of the check is requested (e.g. from
429 ld.c to chk.a), the third parameter is true - in this case the first
430 parameter is the previous check. */
431 rtx (* gen_spec_check) (rtx, rtx, int);
433 /* The following member value is a pointer to a function controlling
434 what insns from the ready insn queue will be considered for the
435 multipass insn scheduling. If the hook returns zero for the insn
436 passed as the parameter, the insn will not be chosen to be
437 issued. This hook is used to discard speculative instructions,
438 that stand at the first position of the ready list. */
439 bool (* first_cycle_multipass_dfa_lookahead_guard_spec) (const_rtx);
441 /* The following member value is a pointer to a function that provides
442 information about the speculation capabilities of the target.
443 The parameter is a pointer to spec_info variable. */
444 void (* set_sched_flags) (struct spec_info_def *);
446 /* Return speculation types of the instruction passed as the parameter. */
447 int (* get_insn_spec_ds) (rtx);
449 /* Return speculation types that are checked for the instruction passed as
451 int (* get_insn_checked_ds) (rtx);
453 /* Return bool if rtx scanning should just skip current layer and
454 advance to the inner rtxes. */
455 bool (* skip_rtx_p) (const_rtx);
457 /* The following member value is a pointer to a function that provides
458 information about the target resource-based lower bound which is
459 used by the swing modulo scheduler. The parameter is a pointer
461 int (* sms_res_mii) (struct ddg *);
464 /* Functions relating to vectorization. */
467 /* The following member value is a pointer to a function called
468 by the vectorizer, and return the decl of the target builtin
470 tree (* builtin_mask_for_load) (void);
472 /* Returns a code for builtin that realizes vectorized version of
473 function, or NULL_TREE if not available. */
474 tree (* builtin_vectorized_function) (unsigned, tree, tree);
476 /* Returns a code for builtin that realizes vectorized version of
477 conversion, or NULL_TREE if not available. */
478 tree (* builtin_conversion) (unsigned, tree);
480 /* Target builtin that implements vector widening multiplication.
481 builtin_mul_widen_eve computes the element-by-element products
482 for the even elements, and builtin_mul_widen_odd computes the
483 element-by-element products for the odd elements. */
484 tree (* builtin_mul_widen_even) (tree);
485 tree (* builtin_mul_widen_odd) (tree);
487 /* Returns the cost to be added to the overheads involved with
488 executing the vectorized version of a loop. */
489 int (*builtin_vectorization_cost) (bool);
491 /* Return true if vector alignment is reachable (by peeling N
492 iterations) for the given type. */
493 bool (* vector_alignment_reachable) (const_tree, bool);
495 /* Target builtin that implements vector permute. */
496 tree (* builtin_vec_perm) (tree, tree*);
498 /* Return true if a vector created for builtin_vec_perm is valid. */
499 bool (* builtin_vec_perm_ok) (tree, tree);
501 /* Return true if the target supports misaligned store/load of a
502 specific factor denoted in the third parameter. The last parameter
503 is true if the access is defined in a packed struct. */
504 bool (* builtin_support_vector_misalignment) (enum machine_mode,
505 const_tree, int, bool);
508 /* The initial value of target_flags. */
509 int default_target_flags;
511 /* Allow target specific overriding of option settings after options have
512 been changed by an attribute or pragma or when it is reset at the
513 end of the code affected by an attribute or pragma. */
514 void (* override_options_after_change) (void);
516 /* Handle target switch CODE (an OPT_* value). ARG is the argument
517 passed to the switch; it is NULL if no argument was. VALUE is the
518 value of ARG if CODE specifies a UInteger option, otherwise it is
519 1 if the positive form of the switch was used and 0 if the negative
520 form was. Return true if the switch was valid. */
521 bool (* handle_option) (size_t code, const char *arg, int value);
523 /* Display extra, target specific information in response to a
524 --target-help switch. */
525 void (* target_help) (void);
527 /* Return machine mode for filter value. */
528 enum machine_mode (* eh_return_filter_mode) (void);
530 /* Return machine mode for libgcc expanded cmp instructions. */
531 enum machine_mode (* libgcc_cmp_return_mode) (void);
533 /* Return machine mode for libgcc expanded shift instructions. */
534 enum machine_mode (* libgcc_shift_count_mode) (void);
536 /* Return machine mode to be used for _Unwind_Word type. */
537 enum machine_mode (* unwind_word_mode) (void);
539 /* Given two decls, merge their attributes and return the result. */
540 tree (* merge_decl_attributes) (tree, tree);
542 /* Given two types, merge their attributes and return the result. */
543 tree (* merge_type_attributes) (tree, tree);
545 /* Table of machine attributes and functions to handle them.
547 const struct attribute_spec *attribute_table;
549 /* Return zero if the attributes on TYPE1 and TYPE2 are incompatible,
550 one if they are compatible and two if they are nearly compatible
551 (which causes a warning to be generated). */
552 int (* comp_type_attributes) (const_tree type1, const_tree type2);
554 /* Assign default attributes to the newly defined TYPE. */
555 void (* set_default_type_attributes) (tree type);
557 /* Insert attributes on the newly created DECL. */
558 void (* insert_attributes) (tree decl, tree *attributes);
560 /* Return true if FNDECL (which has at least one machine attribute)
561 can be inlined despite its machine attributes, false otherwise. */
562 bool (* function_attribute_inlinable_p) (const_tree fndecl);
564 /* Return true if bitfields in RECORD_TYPE should follow the
565 Microsoft Visual C++ bitfield layout rules. */
566 bool (* ms_bitfield_layout_p) (const_tree record_type);
568 /* True if the target supports decimal floating point. */
569 bool (* decimal_float_supported_p) (void);
571 /* True if the target supports fixed-point. */
572 bool (* fixed_point_supported_p) (void);
574 /* Return true if anonymous bitfields affect structure alignment. */
575 bool (* align_anon_bitfield) (void);
577 /* Return true if volatile bitfields should use the narrowest type possible.
578 Return false if they should use the container type. */
579 bool (* narrow_volatile_bitfield) (void);
581 /* Set up target-specific built-in functions. */
582 void (* init_builtins) (void);
584 /* Initialize (if INITIALIZE_P is true) and return the target-specific
585 built-in function decl for CODE.
586 Return NULL if that is not possible. Return error_mark_node if CODE
587 is outside of the range of valid target builtin function codes. */
588 tree (* builtin_decl) (unsigned code, bool initialize_p);
590 /* Expand a target-specific builtin. */
591 rtx (* expand_builtin) (tree exp, rtx target, rtx subtarget,
592 enum machine_mode mode, int ignore);
594 /* Select a replacement for a target-specific builtin. This is done
595 *before* regular type checking, and so allows the target to
596 implement a crude form of function overloading. The result is a
597 complete expression that implements the operation. PARAMS really
598 has type VEC(tree,gc)*, but we don't want to include tree.h
600 tree (*resolve_overloaded_builtin) (unsigned int /*location_t*/,
601 tree decl, void *params);
603 /* Fold a target-specific builtin. */
604 tree (* fold_builtin) (tree fndecl, tree arglist, bool ignore);
606 /* Returns a code for a target-specific builtin that implements
607 reciprocal of the function, or NULL_TREE if not available. */
608 tree (* builtin_reciprocal) (unsigned, bool, bool);
610 /* For a vendor-specific TYPE, return a pointer to a statically-allocated
611 string containing the C++ mangling for TYPE. In all other cases, return
613 const char * (* mangle_type) (const_tree type);
615 /* Make any adjustments to libfunc names needed for this target. */
616 void (* init_libfuncs) (void);
618 /* Given a decl, a section name, and whether the decl initializer
619 has relocs, choose attributes for the section. */
620 /* ??? Should be merged with SELECT_SECTION and UNIQUE_SECTION. */
621 unsigned int (* section_type_flags) (tree, const char *, int);
623 /* True if new jumps cannot be created, to replace existing ones or
624 not, at the current point in the compilation. */
625 bool (* cannot_modify_jumps_p) (void);
627 /* Return a register class for which branch target register
628 optimizations should be applied. */
629 enum reg_class (* branch_target_register_class) (void);
631 /* Return true if branch target register optimizations should include
632 callee-saved registers that are not already live during the current
633 function. AFTER_PE_GEN is true if prologues and epilogues have
634 already been generated. */
635 bool (* branch_target_register_callee_saved) (bool after_pe_gen);
637 /* Return true if the target supports conditional execution. */
638 bool (* have_conditional_execution) (void);
640 /* True if the constant X cannot be placed in the constant pool. */
641 bool (* cannot_force_const_mem) (rtx);
643 /* True if the insn X cannot be duplicated. */
644 bool (* cannot_copy_insn_p) (rtx);
646 /* True if X is considered to be commutative. */
647 bool (* commutative_p) (const_rtx, int);
649 /* Given an invalid address X for a given machine mode, try machine-specific
650 ways to make it legitimate. Return X or an invalid address on failure. */
651 rtx (* legitimize_address) (rtx, rtx, enum machine_mode);
653 /* Given an address RTX, undo the effects of LEGITIMIZE_ADDRESS. */
654 rtx (* delegitimize_address) (rtx);
656 /* Given an address RTX, say whether it is valid. */
657 bool (* legitimate_address_p) (enum machine_mode, rtx, bool);
659 /* True if the given constant can be put into an object_block. */
660 bool (* use_blocks_for_constant_p) (enum machine_mode, const_rtx);
662 /* The minimum and maximum byte offsets for anchored addresses. */
663 HOST_WIDE_INT min_anchor_offset;
664 HOST_WIDE_INT max_anchor_offset;
666 /* True if section anchors can be used to access the given symbol. */
667 bool (* use_anchors_for_symbol_p) (const_rtx);
669 /* True if it is OK to do sibling call optimization for the specified
670 call expression EXP. DECL will be the called function, or NULL if
671 this is an indirect call. */
672 bool (*function_ok_for_sibcall) (tree decl, tree exp);
674 /* Establish appropriate back-end context for processing the function
675 FNDECL. The argument might be NULL to indicate processing at top
676 level, outside of any function scope. */
677 void (*set_current_function) (tree fndecl);
679 /* True if EXP should be placed in a "small data" section. */
680 bool (* in_small_data_p) (const_tree);
682 /* True if EXP names an object for which name resolution must resolve
683 to the current executable or shared library. */
684 bool (* binds_local_p) (const_tree);
686 /* Modify and return the identifier of a DECL's external name,
687 originally identified by ID, as required by the target,
688 (eg, append @nn to windows32 stdcall function names).
689 The default is to return ID without modification. */
690 tree (* mangle_decl_assembler_name) (tree decl, tree id);
692 /* Do something target-specific to record properties of the DECL into
693 the associated SYMBOL_REF. */
694 void (* encode_section_info) (tree, rtx, int);
696 /* Undo the effects of encode_section_info on the symbol string. */
697 const char * (* strip_name_encoding) (const char *);
699 /* If shift optabs for MODE are known to always truncate the shift count,
700 return the mask that they apply. Return 0 otherwise. */
701 unsigned HOST_WIDE_INT (* shift_truncation_mask) (enum machine_mode mode);
703 /* Return the number of divisions in the given MODE that should be present,
704 so that it is profitable to turn the division into a multiplication by
706 unsigned int (* min_divisions_for_recip_mul) (enum machine_mode mode);
708 /* If the representation of integral MODE is such that values are
709 always sign-extended to a wider mode MODE_REP then return
710 SIGN_EXTEND. Return UNKNOWN otherwise. */
711 /* Note that the return type ought to be RTX_CODE, but that's not
712 necessarily defined at this point. */
713 int (* mode_rep_extended) (enum machine_mode mode,
714 enum machine_mode mode_rep);
716 /* True if MODE is valid for a pointer in __attribute__((mode("MODE"))). */
717 bool (* valid_pointer_mode) (enum machine_mode mode);
719 /* Support for named address spaces. */
721 /* MODE to use for a pointer into another address space. */
722 enum machine_mode (* pointer_mode) (addr_space_t);
724 /* MODE to use for an address in another address space. */
725 enum machine_mode (* address_mode) (addr_space_t);
727 /* True if MODE is valid for a pointer in __attribute__((mode("MODE")))
728 in another address space. */
729 bool (* valid_pointer_mode) (enum machine_mode, addr_space_t);
731 /* True if an address is a valid memory address to a given named address
732 space for a given mode. */
733 bool (* legitimate_address_p) (enum machine_mode, rtx, bool, addr_space_t);
735 /* Return an updated address to convert an invalid pointer to a named
736 address space to a valid one. If NULL_RTX is returned use machine
737 independent methods to make the address valid. */
738 rtx (* legitimize_address) (rtx, rtx, enum machine_mode, addr_space_t);
740 /* True if one named address space is a subset of another named address. */
741 bool (* subset_p) (addr_space_t, addr_space_t);
743 /* Function to convert an rtl expression from one address space to
745 rtx (* convert) (rtx, tree, tree);
749 /* True if MODE is valid for the target. By "valid", we mean able to
750 be manipulated in non-trivial ways. In particular, this means all
751 the arithmetic is supported. */
752 bool (* scalar_mode_supported_p) (enum machine_mode mode);
754 /* Similarly for vector modes. "Supported" here is less strict. At
755 least some operations are supported; need to check optabs or builtins
756 for further details. */
757 bool (* vector_mode_supported_p) (enum machine_mode mode);
759 /* Compute a (partial) cost for rtx X. Return true if the complete
760 cost has been computed, and false if subexpressions should be
761 scanned. In either case, *TOTAL contains the cost result. */
762 /* Note that CODE and OUTER_CODE ought to be RTX_CODE, but that's
763 not necessarily defined at this point. */
764 bool (* rtx_costs) (rtx x, int code, int outer_code, int *total, bool speed);
766 /* Compute the cost of X, used as an address. Never called with
767 invalid addresses. */
768 int (* address_cost) (rtx x, bool speed);
770 /* Return where to allocate pseudo for a given hard register initial
772 rtx (* allocate_initial_value) (rtx x);
774 /* Return nonzero if evaluating UNSPEC[_VOLATILE] X might cause a trap.
775 FLAGS has the same meaning as in rtlanal.c: may_trap_p_1. */
776 int (* unspec_may_trap_p) (const_rtx x, unsigned flags);
778 /* Given a register, this hook should return a parallel of registers
779 to represent where to find the register pieces. Define this hook
780 if the register and its mode are represented in Dwarf in
781 non-contiguous locations, or if the register should be
782 represented in more than one register in Dwarf. Otherwise, this
783 hook should return NULL_RTX. */
784 rtx (* dwarf_register_span) (rtx);
786 /* If expand_builtin_init_dwarf_reg_sizes needs to fill in table
787 entries not corresponding directly to registers below
788 FIRST_PSEUDO_REGISTER, this hook should generate the necessary
789 code, given the address of the table. */
790 void (* init_dwarf_reg_sizes_extra) (tree);
792 /* Fetch the fixed register(s) which hold condition codes, for
793 targets where it makes sense to look for duplicate assignments to
794 the condition codes. This should return true if there is such a
795 register, false otherwise. The arguments should be set to the
796 fixed register numbers. Up to two condition code registers are
797 supported. If there is only one for this target, the int pointed
798 at by the second argument should be set to -1. */
799 bool (* fixed_condition_code_regs) (unsigned int *, unsigned int *);
801 /* If two condition code modes are compatible, return a condition
802 code mode which is compatible with both, such that a comparison
803 done in the returned mode will work for both of the original
804 modes. If the condition code modes are not compatible, return
806 enum machine_mode (* cc_modes_compatible) (enum machine_mode,
809 /* Do machine-dependent code transformations. Called just before
810 delayed-branch scheduling. */
811 void (* machine_dependent_reorg) (void);
813 /* Create the __builtin_va_list type. */
814 tree (* build_builtin_va_list) (void);
816 /* Get the cfun/fndecl calling abi __builtin_va_list type. */
817 tree (* fn_abi_va_list) (tree);
819 /* Get the __builtin_va_list type dependent on input type. */
820 tree (* canonical_va_list_type) (tree);
822 /* Expand the __builtin_va_start builtin. */
823 void (* expand_builtin_va_start) (tree valist, rtx nextarg);
825 /* Gimplifies a VA_ARG_EXPR. */
826 tree (* gimplify_va_arg_expr) (tree valist, tree type, gimple_seq *pre_p,
829 /* Validity-checking routines for PCH files, target-specific.
830 get_pch_validity returns a pointer to the data to be stored,
831 and stores the size in its argument. pch_valid_p gets the same
832 information back and returns NULL if the PCH is valid,
833 or an error message if not.
835 void * (* get_pch_validity) (size_t *);
836 const char * (* pch_valid_p) (const void *, size_t);
838 /* If nonnull, this function checks whether a PCH file with the
839 given set of target flags can be used. It returns NULL if so,
840 otherwise it returns an error message. */
841 const char *(*check_pch_target_flags) (int);
843 /* True if the compiler should give an enum type only as many
844 bytes as it takes to represent the range of possible values of
846 bool (* default_short_enums) (void);
848 /* This target hook returns an rtx that is used to store the address
849 of the current frame into the built-in setjmp buffer. */
850 rtx (* builtin_setjmp_frame_value) (void);
852 /* This target hook should add STRING_CST trees for any hard regs
853 the port wishes to automatically clobber for an asm. */
854 tree (* md_asm_clobbers) (tree, tree, tree);
856 /* This target hook allows the backend to specify a calling convention
857 in the debug information. This function actually returns an
858 enum dwarf_calling_convention, but because of forward declarations
859 and not wanting to include dwarf2.h everywhere target.h is included
860 the function is being declared as an int. */
861 int (* dwarf_calling_convention) (const_tree);
863 /* This target hook allows the backend to emit frame-related insns that
864 contain UNSPECs or UNSPEC_VOLATILEs. The call frame debugging info
865 engine will invoke it on insns of the form
866 (set (reg) (unspec [...] UNSPEC_INDEX))
868 (set (reg) (unspec_volatile [...] UNSPECV_INDEX))
869 to let the backend emit the call frame instructions. */
870 void (* dwarf_handle_frame_unspec) (const char *, rtx, int);
872 /* Perform architecture specific checking of statements gimplified
873 from VA_ARG_EXPR. STMT is the statement. Returns true if the statement
874 doesn't need to be checked for va_list references. */
875 bool (* stdarg_optimize_hook) (struct stdarg_info *ai, const_gimple stmt);
877 /* This target hook allows the operating system to override the DECL
878 that represents the external variable that contains the stack
879 protection guard variable. The type of this DECL is ptr_type_node. */
880 tree (* stack_protect_guard) (void);
882 /* This target hook allows the operating system to override the CALL_EXPR
883 that is invoked when a check vs the guard variable fails. */
884 tree (* stack_protect_fail) (void);
886 /* Returns NULL if target supports the insn within a doloop block,
887 otherwise it returns an error message. */
888 const char * (*invalid_within_doloop) (const_rtx);
890 /* DECL is a variable or function with __attribute__((dllimport))
891 specified. Use this hook if the target needs to add extra validation
892 checks to handle_dll_attribute (). */
893 bool (* valid_dllimport_attribute_p) (const_tree decl);
895 /* If non-zero, align constant anchors in CSE to a multiple of this
897 unsigned HOST_WIDE_INT const_anchor;
899 /* Functions relating to calls - argument passing, returns, etc. */
901 enum machine_mode (*promote_function_mode) (const_tree type,
902 enum machine_mode mode,
906 bool (*promote_prototypes) (const_tree fntype);
907 rtx (*struct_value_rtx) (tree fndecl, int incoming);
908 bool (*return_in_memory) (const_tree type, const_tree fndecl);
909 bool (*return_in_msb) (const_tree type);
911 /* Return true if a parameter must be passed by reference. TYPE may
912 be null if this is a libcall. CA may be null if this query is
913 from __builtin_va_arg. */
914 bool (*pass_by_reference) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
915 const_tree type, bool named_arg);
917 rtx (*expand_builtin_saveregs) (void);
918 /* Returns pretend_argument_size. */
919 void (*setup_incoming_varargs) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
920 tree type, int *pretend_arg_size,
922 bool (*strict_argument_naming) (CUMULATIVE_ARGS *ca);
923 /* Returns true if we should use
924 targetm.calls.setup_incoming_varargs() and/or
925 targetm.calls.strict_argument_naming(). */
926 bool (*pretend_outgoing_varargs_named) (CUMULATIVE_ARGS *ca);
928 /* Given a complex type T, return true if a parameter of type T
929 should be passed as two scalars. */
930 bool (* split_complex_arg) (const_tree type);
932 /* Return true if type T, mode MODE, may not be passed in registers,
933 but must be passed on the stack. */
934 /* ??? This predicate should be applied strictly after pass-by-reference.
935 Need audit to verify that this is the case. */
936 bool (* must_pass_in_stack) (enum machine_mode mode, const_tree t);
938 /* Return true if type TYPE, mode MODE, which is passed by reference,
939 should have the object copy generated by the callee rather than
940 the caller. It is never called for TYPE requiring constructors. */
941 bool (* callee_copies) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
942 const_tree type, bool named);
944 /* Return zero for arguments passed entirely on the stack or entirely
945 in registers. If passed in both, return the number of bytes passed
946 in registers; the balance is therefore passed on the stack. */
947 int (* arg_partial_bytes) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
948 tree type, bool named);
950 /* Return the diagnostic message string if function without a prototype
951 is not allowed for this 'val' argument; NULL otherwise. */
952 const char *(*invalid_arg_for_unprototyped_fn) (const_tree typelist,
956 /* Return an rtx for the return value location of the function
957 specified by FN_DECL_OR_TYPE with a return type of RET_TYPE. */
958 rtx (*function_value) (const_tree ret_type, const_tree fn_decl_or_type,
961 /* Return the rtx for the result of a libcall of mode MODE,
962 calling the function FN_NAME. */
963 rtx (*libcall_value) (enum machine_mode, const_rtx);
965 /* Return an rtx for the argument pointer incoming to the
967 rtx (*internal_arg_pointer) (void);
969 /* Update the current function stack boundary if needed. */
970 void (*update_stack_boundary) (void);
972 /* Handle stack alignment and return an rtx for Dynamic Realign
973 Argument Pointer if necessary. */
974 rtx (*get_drap_rtx) (void);
976 /* Return true if all function parameters should be spilled to the
978 bool (*allocate_stack_slots_for_args) (void);
980 /* Return an rtx for the static chain for FNDECL. If INCOMING_P is true,
981 then it should be for the callee; otherwise for the caller. */
982 rtx (*static_chain) (const_tree fndecl, bool incoming_p);
984 /* Fill in the trampoline at MEM with a call to FNDECL and a
985 static chain value of CHAIN. */
986 void (*trampoline_init) (rtx mem, tree fndecl, rtx chain);
988 /* Adjust the address of the trampoline in a target-specific way. */
989 rtx (*trampoline_adjust_address) (rtx addr);
992 /* Return the diagnostic message string if conversion from FROMTYPE
993 to TOTYPE is not allowed, NULL otherwise. */
994 const char *(*invalid_conversion) (const_tree fromtype, const_tree totype);
996 /* Return the diagnostic message string if the unary operation OP is
997 not permitted on TYPE, NULL otherwise. */
998 const char *(*invalid_unary_op) (int op, const_tree type);
1000 /* Return the diagnostic message string if the binary operation OP
1001 is not permitted on TYPE1 and TYPE2, NULL otherwise. */
1002 const char *(*invalid_binary_op) (int op, const_tree type1, const_tree type2);
1004 /* Return the diagnostic message string if TYPE is not valid as a
1005 function parameter type, NULL otherwise. */
1006 const char *(*invalid_parameter_type) (const_tree type);
1008 /* Return the diagnostic message string if TYPE is not valid as a
1009 function return type, NULL otherwise. */
1010 const char *(*invalid_return_type) (const_tree type);
1012 /* If values of TYPE are promoted to some other type when used in
1013 expressions (analogous to the integer promotions), return that type,
1014 or NULL_TREE otherwise. */
1015 tree (*promoted_type) (const_tree type);
1017 /* Convert EXPR to TYPE, if target-specific types with special conversion
1018 rules are involved. Return the converted expression, or NULL to apply
1019 the standard conversion rules. */
1020 tree (*convert_to_type) (tree type, tree expr);
1022 /* Return the array of IRA cover classes for the current target. */
1023 const enum reg_class *(*ira_cover_classes) (void);
1025 /* Return the class for a secondary reload, and fill in extra information. */
1026 enum reg_class (*secondary_reload) (bool, rtx, enum reg_class,
1028 secondary_reload_info *);
1030 /* This target hook allows the backend to perform additional
1031 processing while initializing for variable expansion. */
1032 void (* expand_to_rtl_hook) (void);
1034 /* This target hook allows the backend to perform additional
1035 instantiations on rtx that are not actually in insns yet,
1036 but will be later. */
1037 void (* instantiate_decls) (void);
1039 /* Return true if is OK to use a hard register REGNO as scratch register
1041 bool (* hard_regno_scratch_ok) (unsigned int regno);
1043 /* Return the smallest number of different values for which it is best to
1044 use a jump-table instead of a tree of conditional branches. */
1045 unsigned int (* case_values_threshold) (void);
1047 /* Retutn true if a function must have and use a frame pointer. */
1048 bool (* frame_pointer_required) (void);
1050 /* Returns true if the compiler is allowed to try to replace register number
1051 from-reg with register number to-reg. */
1052 bool (* can_eliminate) (const int, const int);
1054 /* Functions specific to the C family of frontends. */
1056 /* Return machine mode for non-standard suffix
1057 or VOIDmode if non-standard suffixes are unsupported. */
1058 enum machine_mode (*mode_for_suffix) (char);
1061 /* Functions specific to the C++ frontend. */
1063 /* Return the integer type used for guard variables. */
1064 tree (*guard_type) (void);
1065 /* Return true if only the low bit of the guard should be tested. */
1066 bool (*guard_mask_bit) (void);
1067 /* Returns the size of the array cookie for an array of type. */
1068 tree (*get_cookie_size) (tree);
1069 /* Returns true if the element size should be stored in the
1071 bool (*cookie_has_size) (void);
1072 /* Allows backends to perform additional processing when
1073 deciding if a class should be exported or imported. */
1074 int (*import_export_class) (tree, int);
1075 /* Returns true if constructors and destructors return "this". */
1076 bool (*cdtor_returns_this) (void);
1077 /* Returns true if the key method for a class can be an inline
1078 function, so long as it is not declared inline in the class
1079 itself. Returning true is the behavior required by the Itanium
1081 bool (*key_method_may_be_inline) (void);
1082 /* DECL is a virtual table, virtual table table, typeinfo object,
1083 or other similar implicit class data object that will be
1084 emitted with external linkage in this translation unit. No ELF
1085 visibility has been explicitly specified. If the target needs
1086 to specify a visibility other than that of the containing class,
1087 use this hook to set DECL_VISIBILITY and
1088 DECL_VISIBILITY_SPECIFIED. */
1089 void (*determine_class_data_visibility) (tree decl);
1090 /* Returns true (the default) if virtual tables and other
1091 similar implicit class data objects are always COMDAT if they
1092 have external linkage. If this hook returns false, then
1093 class data for classes whose virtual table will be emitted in
1094 only one translation unit will not be COMDAT. */
1095 bool (*class_data_always_comdat) (void);
1096 /* Returns true (the default) if the RTTI for the basic types,
1097 which is always defined in the C++ runtime, should be COMDAT;
1098 false if it should not be COMDAT. */
1099 bool (*library_rtti_comdat) (void);
1100 /* Returns true if __aeabi_atexit should be used to register static
1102 bool (*use_aeabi_atexit) (void);
1103 /* Returns true if target may use atexit in the same manner as
1104 __cxa_atexit to register static destructors. */
1105 bool (*use_atexit_for_cxa_atexit) (void);
1106 /* TYPE is a C++ class (i.e., RECORD_TYPE or UNION_TYPE) that
1107 has just been defined. Use this hook to make adjustments to the
1108 class (eg, tweak visibility or perform any other required
1109 target modifications). */
1110 void (*adjust_class_at_definition) (tree type);
1113 /* Functions and data for emulated TLS support. */
1115 /* Name of the address and common functions. */
1116 const char *get_address;
1117 const char *register_common;
1119 /* Prefixes for proxy variable and template. */
1120 const char *var_section;
1121 const char *tmpl_section;
1123 /* Prefixes for proxy variable and template. */
1124 const char *var_prefix;
1125 const char *tmpl_prefix;
1127 /* Function to generate field definitions of the proxy variable. */
1128 tree (*var_fields) (tree, tree *);
1130 /* Function to initialize a proxy variable. */
1131 tree (*var_init) (tree, tree, tree);
1133 /* Whether we are allowed to alter the usual alignment of the
1135 bool var_align_fixed;
1137 /* Whether we can emit debug information for TLS vars. */
1138 bool debug_form_tls_address;
1141 struct target_option_hooks {
1142 /* Function to validate the attribute((option(...))) strings or NULL. If
1143 the option is validated, it is assumed that DECL_FUNCTION_SPECIFIC will
1144 be filled in in the function decl node. */
1145 bool (*valid_attribute_p) (tree, tree, tree, int);
1147 /* Function to save any extra target state in the target options
1149 void (*save) (struct cl_target_option *);
1151 /* Function to restore any extra target state from the target options
1153 void (*restore) (struct cl_target_option *);
1155 /* Function to print any extra target state from the target options
1157 void (*print) (FILE *, int, struct cl_target_option *);
1159 /* Function to parse arguments to be validated for #pragma option, and to
1160 change the state if the options are valid. If the first argument is
1161 NULL, the second argument specifies the default options to use. Return
1162 true if the options are valid, and set the current state. */
1163 bool (*pragma_parse) (tree, tree);
1165 /* Function to determine if one function can inline another function. */
1166 bool (*can_inline_p) (tree, tree);
1169 /* For targets that need to mark extra registers as live on entry to
1170 the function, they should define this target hook and set their
1171 bits in the bitmap passed in. */
1172 void (*live_on_entry) (bitmap);
1174 /* True if unwinding tables should be generated by default. */
1175 bool unwind_tables_default;
1177 /* Leave the boolean fields at the end. */
1179 /* True if arbitrary sections are supported. */
1180 bool have_named_sections;
1182 /* True if we can create zeroed data by switching to a BSS section
1183 and then using ASM_OUTPUT_SKIP to allocate the space. */
1184 bool have_switchable_bss_sections;
1186 /* True if "native" constructors and destructors are supported,
1187 false if we're using collect2 for the job. */
1188 bool have_ctors_dtors;
1190 /* True if thread-local storage is supported. */
1193 /* True if a small readonly data section is supported. */
1194 bool have_srodata_section;
1196 /* True if EH frame info sections should be zero-terminated. */
1197 bool terminate_dw2_eh_frame_info;
1199 /* True if #NO_APP should be emitted at the beginning of
1201 bool file_start_app_off;
1203 /* True if output_file_directive should be called for main_input_filename
1204 at the beginning of assembly output. */
1205 bool file_start_file_directive;
1207 /* True if #pragma extern_prefix is to be supported. */
1208 bool handle_pragma_extern_prefix;
1210 /* True if the target is allowed to reorder memory accesses unless
1211 synchronization is explicitly requested. */
1212 bool relaxed_ordering;
1214 /* Returns true if we should generate exception tables for use with the
1215 ARM EABI. The effects the encoding of function exception specifications.
1217 bool arm_eabi_unwinder;
1219 /* Leave the boolean fields at the end. */
1222 extern struct gcc_target targetm;
1224 struct gcc_targetcm {
1225 /* Handle target switch CODE (an OPT_* value). ARG is the argument
1226 passed to the switch; it is NULL if no argument was. VALUE is the
1227 value of ARG if CODE specifies a UInteger option, otherwise it is
1228 1 if the positive form of the switch was used and 0 if the negative
1229 form was. Return true if the switch was valid. */
1230 bool (*handle_c_option) (size_t code, const char *arg, int value);
1233 /* Each target can provide their own. */
1234 extern struct gcc_targetcm targetcm;
1236 #endif /* GCC_TARGET_H */
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