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. 4 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 8 later version. 9 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. 14 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/>. 18 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! */ 22 23 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 27 information. 28 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 31 macros. 32 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 38 "targetm" like so: 39 40 struct gcc_target targetm = TARGET_INITIALIZER; 41 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. */ 48 49 #ifndef GCC_TARGET_H 50 #define GCC_TARGET_H 51 52 #include "tm.h" 53 #include "insn-modes.h" 54 55 /* Types used by the record_gcc_switches() target function. */ 56 typedef enum 57 { 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. */ 63 } 64 print_switch_type; 65 66 typedef int (* print_switch_fn_type) (print_switch_type, const char *); 67 68 /* An example implementation for ELF targets. Defined in varasm.c */ 69 extern int elf_record_gcc_switches (print_switch_type type, const char *); 70 71 struct stdarg_info; 72 struct spec_info_def; 73 74 /* The struct used by the secondary_reload target hook. */ 75 typedef struct secondary_reload_info 76 { 77 /* icode is actually an enum insn_code, but we don't want to force every 78 file that includes target.h to include optabs.h . */ 79 int icode; 80 int extra_cost; /* Cost for using (a) scratch register(s) to be taken 81 into account by copy_cost. */ 82 /* The next two members are for the use of the backward 83 compatibility hook. */ 84 struct secondary_reload_info *prev_sri; 85 int t_icode; /* Actually an enum insn_code - see above. */ 86 } secondary_reload_info; 87 88 /* This is defined in sched-int.h . */ 89 struct _dep; 90 91 /* This is defined in ddg.h . */ 92 struct ddg; 93 94 struct gcc_target 95 { 96 /* Functions that output assembler for the target. */ 97 struct asm_out 98 { 99 /* Opening and closing parentheses for asm expression grouping. */ 100 const char *open_paren, *close_paren; 101 102 /* Assembler instructions for creating various kinds of integer object. */ 103 const char *byte_op; 104 struct asm_int_op 105 { 106 const char *hi; 107 const char *si; 108 const char *di; 109 const char *ti; 110 } aligned_op, unaligned_op; 111 112 /* Try to output the assembler code for an integer object whose 113 value is given by X. SIZE is the size of the object in bytes and 114 ALIGNED_P indicates whether it is aligned. Return true if 115 successful. Only handles cases for which BYTE_OP, ALIGNED_OP 116 and UNALIGNED_OP are NULL. */ 117 bool (* integer) (rtx x, unsigned int size, int aligned_p); 118 119 /* Output code that will globalize a label. */ 120 void (* globalize_label) (FILE *, const char *); 121 122 /* Output code that will globalize a declaration. */ 123 void (* globalize_decl_name) (FILE *, tree); 124 125 /* Output code that will emit a label for unwind info, if this 126 target requires such labels. Second argument is the decl the 127 unwind info is associated with, third is a boolean: true if 128 this is for exception handling, fourth is a boolean: true if 129 this is only a placeholder for an omitted FDE. */ 130 void (* unwind_label) (FILE *, tree, int, int); 131 132 /* Output code that will emit a label to divide up the exception 133 table. */ 134 void (* except_table_label) (FILE *); 135 136 /* Emit any directives required to unwind this instruction. */ 137 void (* unwind_emit) (FILE *, rtx); 138 139 /* Output an internal label. */ 140 void (* internal_label) (FILE *, const char *, unsigned long); 141 142 /* Emit a ttype table reference to a typeinfo object. */ 143 bool (* ttype) (rtx); 144 145 /* Emit an assembler directive to set visibility for the symbol 146 associated with the tree decl. */ 147 void (* visibility) (tree, int); 148 149 /* Output the assembler code for entry to a function. */ 150 void (* function_prologue) (FILE *, HOST_WIDE_INT); 151 152 /* Output the assembler code for end of prologue. */ 153 void (* function_end_prologue) (FILE *); 154 155 /* Output the assembler code for start of epilogue. */ 156 void (* function_begin_epilogue) (FILE *); 157 158 /* Output the assembler code for function exit. */ 159 void (* function_epilogue) (FILE *, HOST_WIDE_INT); 160 161 /* Initialize target-specific sections. */ 162 void (* init_sections) (void); 163 164 /* Tell assembler to change to section NAME with attributes FLAGS. 165 If DECL is non-NULL, it is the VAR_DECL or FUNCTION_DECL with 166 which this section is associated. */ 167 void (* named_section) (const char *name, unsigned int flags, tree decl); 168 169 /* Return a mask describing how relocations should be treated when 170 selecting sections. Bit 1 should be set if global relocations 171 should be placed in a read-write section; bit 0 should be set if 172 local relocations should be placed in a read-write section. */ 173 int (*reloc_rw_mask) (void); 174 175 /* Return a section for EXP. It may be a DECL or a constant. RELOC 176 is nonzero if runtime relocations must be applied; bit 1 will be 177 set if the runtime relocations require non-local name resolution. 178 ALIGN is the required alignment of the data. */ 179 section *(* select_section) (tree, int, unsigned HOST_WIDE_INT); 180 181 /* Return a section for X. MODE is X's mode and ALIGN is its 182 alignment in bits. */ 183 section *(* select_rtx_section) (enum machine_mode, rtx, 184 unsigned HOST_WIDE_INT); 185 186 /* Select a unique section name for DECL. RELOC is the same as 187 for SELECT_SECTION. */ 188 void (* unique_section) (tree, int); 189 190 /* Return the readonly data section associated with function DECL. */ 191 section *(* function_rodata_section) (tree); 192 193 /* Output a constructor for a symbol with a given priority. */ 194 void (* constructor) (rtx, int); 195 196 /* Output a destructor for a symbol with a given priority. */ 197 void (* destructor) (rtx, int); 198 199 /* Output the assembler code for a thunk function. THUNK_DECL is the 200 declaration for the thunk function itself, FUNCTION is the decl for 201 the target function. DELTA is an immediate constant offset to be 202 added to THIS. If VCALL_OFFSET is nonzero, the word at 203 *(*this + vcall_offset) should be added to THIS. */ 204 void (* output_mi_thunk) (FILE *file, tree thunk_decl, 205 HOST_WIDE_INT delta, HOST_WIDE_INT vcall_offset, 206 tree function_decl); 207 208 /* Determine whether output_mi_thunk would succeed. */ 209 /* ??? Ideally, this hook would not exist, and success or failure 210 would be returned from output_mi_thunk directly. But there's 211 too much undo-able setup involved in invoking output_mi_thunk. 212 Could be fixed by making output_mi_thunk emit rtl instead of 213 text to the output file. */ 214 bool (* can_output_mi_thunk) (const_tree thunk_decl, HOST_WIDE_INT delta, 215 HOST_WIDE_INT vcall_offset, 216 const_tree function_decl); 217 218 /* Output any boilerplate text needed at the beginning of a 219 translation unit. */ 220 void (*file_start) (void); 221 222 /* Output any boilerplate text needed at the end of a 223 translation unit. */ 224 void (*file_end) (void); 225 226 /* Output an assembler pseudo-op to declare a library function name 227 external. */ 228 void (*external_libcall) (rtx); 229 230 /* Output an assembler directive to mark decl live. This instructs 231 linker to not dead code strip this symbol. */ 232 void (*mark_decl_preserved) (const char *); 233 234 /* Output a record of the command line switches that have been passed. */ 235 print_switch_fn_type record_gcc_switches; 236 /* The name of the section that the example ELF implementation of 237 record_gcc_switches will use to store the information. Target 238 specific versions of record_gcc_switches may or may not use 239 this information. */ 240 const char * record_gcc_switches_section; 241 242 /* Output the definition of a section anchor. */ 243 void (*output_anchor) (rtx); 244 245 /* Output a DTP-relative reference to a TLS symbol. */ 246 void (*output_dwarf_dtprel) (FILE *file, int size, rtx x); 247 248 } asm_out; 249 250 /* Functions relating to instruction scheduling. */ 251 struct sched 252 { 253 /* Given the current cost, COST, of an insn, INSN, calculate and 254 return a new cost based on its relationship to DEP_INSN through 255 the dependence LINK. The default is to make no adjustment. */ 256 int (* adjust_cost) (rtx insn, rtx link, rtx dep_insn, int cost); 257 258 /* Adjust the priority of an insn as you see fit. Returns the new 259 priority. */ 260 int (* adjust_priority) (rtx, int); 261 262 /* Function which returns the maximum number of insns that can be 263 scheduled in the same machine cycle. This must be constant 264 over an entire compilation. The default is 1. */ 265 int (* issue_rate) (void); 266 267 /* Calculate how much this insn affects how many more insns we 268 can emit this cycle. Default is they all cost the same. */ 269 int (* variable_issue) (FILE *, int, rtx, int); 270 271 /* Initialize machine-dependent scheduling code. */ 272 void (* md_init) (FILE *, int, int); 273 274 /* Finalize machine-dependent scheduling code. */ 275 void (* md_finish) (FILE *, int); 276 277 /* Initialize machine-dependent function wide scheduling code. */ 278 void (* md_init_global) (FILE *, int, int); 279 280 /* Finalize machine-dependent function wide scheduling code. */ 281 void (* md_finish_global) (FILE *, int); 282 283 /* Reorder insns in a machine-dependent fashion, in two different 284 places. Default does nothing. */ 285 int (* reorder) (FILE *, int, rtx *, int *, int); 286 int (* reorder2) (FILE *, int, rtx *, int *, int); 287 288 /* The following member value is a pointer to a function called 289 after evaluation forward dependencies of insns in chain given 290 by two parameter values (head and tail correspondingly). */ 291 void (* dependencies_evaluation_hook) (rtx, rtx); 292 293 /* The values of the following four members are pointers to 294 functions used to simplify the automaton descriptions. 295 dfa_pre_cycle_insn and dfa_post_cycle_insn give functions 296 returning insns which are used to change the pipeline hazard 297 recognizer state when the new simulated processor cycle 298 correspondingly starts and finishes. The function defined by 299 init_dfa_pre_cycle_insn and init_dfa_post_cycle_insn are used 300 to initialize the corresponding insns. The default values of 301 the members result in not changing the automaton state when 302 the new simulated processor cycle correspondingly starts and 303 finishes. */ 304 void (* init_dfa_pre_cycle_insn) (void); 305 rtx (* dfa_pre_cycle_insn) (void); 306 void (* init_dfa_post_cycle_insn) (void); 307 rtx (* dfa_post_cycle_insn) (void); 308 309 /* The values of the following two members are pointers to 310 functions used to simplify the automaton descriptions. 311 dfa_pre_advance_cycle and dfa_post_advance_cycle are getting called 312 immediately before and after cycle is advanced. */ 313 void (* dfa_pre_advance_cycle) (void); 314 void (* dfa_post_advance_cycle) (void); 315 316 /* The following member value is a pointer to a function returning value 317 which defines how many insns in queue `ready' will we try for 318 multi-pass scheduling. If the member value is nonzero and the 319 function returns positive value, the DFA based scheduler will make 320 multi-pass scheduling for the first cycle. In other words, we will 321 try to choose ready insn which permits to start maximum number of 322 insns on the same cycle. */ 323 int (* first_cycle_multipass_dfa_lookahead) (void); 324 325 /* The following member value is pointer to a function controlling 326 what insns from the ready insn queue will be considered for the 327 multipass insn scheduling. If the hook returns zero for insn 328 passed as the parameter, the insn will be not chosen to be 329 issued. */ 330 int (* first_cycle_multipass_dfa_lookahead_guard) (rtx); 331 332 /* The following member value is pointer to a function called by 333 the insn scheduler before issuing insn passed as the third 334 parameter on given cycle. If the hook returns nonzero, the 335 insn is not issued on given processors cycle. Instead of that, 336 the processor cycle is advanced. If the value passed through 337 the last parameter is zero, the insn ready queue is not sorted 338 on the new cycle start as usually. The first parameter passes 339 file for debugging output. The second one passes the scheduler 340 verbose level of the debugging output. The forth and the fifth 341 parameter values are correspondingly processor cycle on which 342 the previous insn has been issued and the current processor 343 cycle. */ 344 int (* dfa_new_cycle) (FILE *, int, rtx, int, int, int *); 345 346 /* The following member value is a pointer to a function called by the 347 insn scheduler. It should return true if there exists a dependence 348 which is considered costly by the target, between the insn 349 DEP_PRO (&_DEP), and the insn DEP_CON (&_DEP). The first parameter is 350 the dep that represents the dependence between the two insns. The 351 second argument is the cost of the dependence as estimated by 352 the scheduler. The last argument is the distance in cycles 353 between the already scheduled insn (first parameter) and the 354 second insn (second parameter). */ 355 bool (* is_costly_dependence) (struct _dep *_dep, int, int); 356 357 /* Given the current cost, COST, of an insn, INSN, calculate and 358 return a new cost based on its relationship to DEP_INSN through the 359 dependence of type DEP_TYPE. The default is to make no adjustment. */ 360 int (* adjust_cost_2) (rtx insn, int, rtx dep_insn, int cost, int dw); 361 362 /* The following member value is a pointer to a function called 363 by the insn scheduler. This hook is called to notify the backend 364 that new instructions were emitted. */ 365 void (* h_i_d_extended) (void); 366 367 /* Next 5 functions are for multi-point scheduling. */ 368 369 /* Allocate memory for scheduler context. */ 370 void *(* alloc_sched_context) (void); 371 372 /* Fills the context from the local machine scheduler context. */ 373 void (* init_sched_context) (void *, bool); 374 375 /* Sets local machine scheduler context to a saved value. */ 376 void (* set_sched_context) (void *); 377 378 /* Clears a scheduler context so it becomes like after init. */ 379 void (* clear_sched_context) (void *); 380 381 /* Frees the scheduler context. */ 382 void (* free_sched_context) (void *); 383 384 /* The following member value is a pointer to a function called 385 by the insn scheduler. 386 The first parameter is an instruction, the second parameter is the type 387 of the requested speculation, and the third parameter is a pointer to the 388 speculative pattern of the corresponding type (set if return value == 1). 389 It should return 390 -1, if there is no pattern, that will satisfy the requested speculation 391 type, 392 0, if current pattern satisfies the requested speculation type, 393 1, if pattern of the instruction should be changed to the newly 394 generated one. */ 395 int (* speculate_insn) (rtx, int, rtx *); 396 397 /* The following member value is a pointer to a function called 398 by the insn scheduler. It should return true if the check instruction 399 passed as the parameter needs a recovery block. */ 400 bool (* needs_block_p) (int); 401 402 /* The following member value is a pointer to a function called 403 by the insn scheduler. It should return a pattern for the check 404 instruction. 405 The first parameter is a speculative instruction, the second parameter 406 is the label of the corresponding recovery block (or null, if it is a 407 simple check). If the mutation of the check is requested (e.g. from 408 ld.c to chk.a), the third parameter is true - in this case the first 409 parameter is the previous check. */ 410 rtx (* gen_spec_check) (rtx, rtx, int); 411 412 /* The following member value is a pointer to a function controlling 413 what insns from the ready insn queue will be considered for the 414 multipass insn scheduling. If the hook returns zero for the insn 415 passed as the parameter, the insn will not be chosen to be 416 issued. This hook is used to discard speculative instructions, 417 that stand at the first position of the ready list. */ 418 bool (* first_cycle_multipass_dfa_lookahead_guard_spec) (const_rtx); 419 420 /* The following member value is a pointer to a function that provides 421 information about the speculation capabilities of the target. 422 The parameter is a pointer to spec_info variable. */ 423 void (* set_sched_flags) (struct spec_info_def *); 424 425 /* Return speculation types of the instruction passed as the parameter. */ 426 int (* get_insn_spec_ds) (rtx); 427 428 /* Return speculation types that are checked for the instruction passed as 429 the parameter. */ 430 int (* get_insn_checked_ds) (rtx); 431 432 /* Return bool if rtx scanning should just skip current layer and 433 advance to the inner rtxes. */ 434 bool (* skip_rtx_p) (const_rtx); 435 436 /* The following member value is a pointer to a function that provides 437 information about the target resource-based lower bound which is 438 used by the swing modulo scheduler. The parameter is a pointer 439 to ddg variable. */ 440 int (* sms_res_mii) (struct ddg *); 441 } sched; 442 443 /* Functions relating to vectorization. */ 444 struct vectorize 445 { 446 /* The following member value is a pointer to a function called 447 by the vectorizer, and return the decl of the target builtin 448 function. */ 449 tree (* builtin_mask_for_load) (void); 450 451 /* Returns a code for builtin that realizes vectorized version of 452 function, or NULL_TREE if not available. */ 453 tree (* builtin_vectorized_function) (unsigned, tree, tree); 454 455 /* Returns a code for builtin that realizes vectorized version of 456 conversion, or NULL_TREE if not available. */ 457 tree (* builtin_conversion) (unsigned, tree); 458 459 /* Target builtin that implements vector widening multiplication. 460 builtin_mul_widen_eve computes the element-by-element products 461 for the even elements, and builtin_mul_widen_odd computes the 462 element-by-element products for the odd elements. */ 463 tree (* builtin_mul_widen_even) (tree); 464 tree (* builtin_mul_widen_odd) (tree); 465 466 /* Returns the cost to be added to the overheads involved with 467 executing the vectorized version of a loop. */ 468 int (*builtin_vectorization_cost) (bool); 469 470 /* Return true if vector alignment is reachable (by peeling N 471 iterations) for the given type. */ 472 bool (* vector_alignment_reachable) (const_tree, bool); 473 474 /* Target builtin that implements vector permute. */ 475 tree (* builtin_vec_perm) (tree, tree*); 476 } vectorize; 477 478 /* The initial value of target_flags. */ 479 int default_target_flags; 480 481 /* Handle target switch CODE (an OPT_* value). ARG is the argument 482 passed to the switch; it is NULL if no argument was. VALUE is the 483 value of ARG if CODE specifies a UInteger option, otherwise it is 484 1 if the positive form of the switch was used and 0 if the negative 485 form was. Return true if the switch was valid. */ 486 bool (* handle_option) (size_t code, const char *arg, int value); 487 488 /* Display extra, target specific information in response to a 489 --target-help switch. */ 490 void (* target_help) (void); 491 492 /* Return machine mode for filter value. */ 493 enum machine_mode (* eh_return_filter_mode) (void); 494 495 /* Return machine mode for libgcc expanded cmp instructions. */ 496 enum machine_mode (* libgcc_cmp_return_mode) (void); 497 498 /* Return machine mode for libgcc expanded shift instructions. */ 499 enum machine_mode (* libgcc_shift_count_mode) (void); 500 501 /* Return machine mode to be used for _Unwind_Word type. */ 502 enum machine_mode (* unwind_word_mode) (void); 503 504 /* Given two decls, merge their attributes and return the result. */ 505 tree (* merge_decl_attributes) (tree, tree); 506 507 /* Given two types, merge their attributes and return the result. */ 508 tree (* merge_type_attributes) (tree, tree); 509 510 /* Table of machine attributes and functions to handle them. 511 Ignored if NULL. */ 512 const struct attribute_spec *attribute_table; 513 514 /* Return zero if the attributes on TYPE1 and TYPE2 are incompatible, 515 one if they are compatible and two if they are nearly compatible 516 (which causes a warning to be generated). */ 517 int (* comp_type_attributes) (const_tree type1, const_tree type2); 518 519 /* Assign default attributes to the newly defined TYPE. */ 520 void (* set_default_type_attributes) (tree type); 521 522 /* Insert attributes on the newly created DECL. */ 523 void (* insert_attributes) (tree decl, tree *attributes); 524 525 /* Return true if FNDECL (which has at least one machine attribute) 526 can be inlined despite its machine attributes, false otherwise. */ 527 bool (* function_attribute_inlinable_p) (const_tree fndecl); 528 529 /* Return true if bitfields in RECORD_TYPE should follow the 530 Microsoft Visual C++ bitfield layout rules. */ 531 bool (* ms_bitfield_layout_p) (const_tree record_type); 532 533 /* True if the target supports decimal floating point. */ 534 bool (* decimal_float_supported_p) (void); 535 536 /* True if the target supports fixed-point. */ 537 bool (* fixed_point_supported_p) (void); 538 539 /* Return true if anonymous bitfields affect structure alignment. */ 540 bool (* align_anon_bitfield) (void); 541 542 /* Return true if volatile bitfields should use the narrowest type possible. 543 Return false if they should use the container type. */ 544 bool (* narrow_volatile_bitfield) (void); 545 546 /* Set up target-specific built-in functions. */ 547 void (* init_builtins) (void); 548 549 /* Expand a target-specific builtin. */ 550 rtx (* expand_builtin) (tree exp, rtx target, rtx subtarget, 551 enum machine_mode mode, int ignore); 552 553 /* Select a replacement for a target-specific builtin. This is done 554 *before* regular type checking, and so allows the target to implement 555 a crude form of function overloading. The result is a complete 556 expression that implements the operation. */ 557 tree (*resolve_overloaded_builtin) (tree decl, tree params); 558 559 /* Fold a target-specific builtin. */ 560 tree (* fold_builtin) (tree fndecl, tree arglist, bool ignore); 561 562 /* Returns a code for a target-specific builtin that implements 563 reciprocal of the function, or NULL_TREE if not available. */ 564 tree (* builtin_reciprocal) (unsigned, bool, bool); 565 566 /* For a vendor-specific TYPE, return a pointer to a statically-allocated 567 string containing the C++ mangling for TYPE. In all other cases, return 568 NULL. */ 569 const char * (* mangle_type) (const_tree type); 570 571 /* Make any adjustments to libfunc names needed for this target. */ 572 void (* init_libfuncs) (void); 573 574 /* Given a decl, a section name, and whether the decl initializer 575 has relocs, choose attributes for the section. */ 576 /* ??? Should be merged with SELECT_SECTION and UNIQUE_SECTION. */ 577 unsigned int (* section_type_flags) (tree, const char *, int); 578 579 /* True if new jumps cannot be created, to replace existing ones or 580 not, at the current point in the compilation. */ 581 bool (* cannot_modify_jumps_p) (void); 582 583 /* Return a register class for which branch target register 584 optimizations should be applied. */ 585 int (* branch_target_register_class) (void); 586 587 /* Return true if branch target register optimizations should include 588 callee-saved registers that are not already live during the current 589 function. AFTER_PE_GEN is true if prologues and epilogues have 590 already been generated. */ 591 bool (* branch_target_register_callee_saved) (bool after_pe_gen); 592 593 /* Return true if the target supports conditional execution. */ 594 bool (* have_conditional_execution) (void); 595 596 /* True if the constant X cannot be placed in the constant pool. */ 597 bool (* cannot_force_const_mem) (rtx); 598 599 /* True if the insn X cannot be duplicated. */ 600 bool (* cannot_copy_insn_p) (rtx); 601 602 /* True if X is considered to be commutative. */ 603 bool (* commutative_p) (const_rtx, int); 604 605 /* Given an address RTX, undo the effects of LEGITIMIZE_ADDRESS. */ 606 rtx (* delegitimize_address) (rtx); 607 608 /* True if the given constant can be put into an object_block. */ 609 bool (* use_blocks_for_constant_p) (enum machine_mode, const_rtx); 610 611 /* The minimum and maximum byte offsets for anchored addresses. */ 612 HOST_WIDE_INT min_anchor_offset; 613 HOST_WIDE_INT max_anchor_offset; 614 615 /* True if section anchors can be used to access the given symbol. */ 616 bool (* use_anchors_for_symbol_p) (const_rtx); 617 618 /* True if it is OK to do sibling call optimization for the specified 619 call expression EXP. DECL will be the called function, or NULL if 620 this is an indirect call. */ 621 bool (*function_ok_for_sibcall) (tree decl, tree exp); 622 623 /* Establish appropriate back-end context for processing the function 624 FNDECL. The argument might be NULL to indicate processing at top 625 level, outside of any function scope. */ 626 void (*set_current_function) (tree fndecl); 627 628 /* True if EXP should be placed in a "small data" section. */ 629 bool (* in_small_data_p) (const_tree); 630 631 /* True if EXP names an object for which name resolution must resolve 632 to the current executable or shared library. */ 633 bool (* binds_local_p) (const_tree); 634 635 /* Modify and return the identifier of a DECL's external name, 636 originally identified by ID, as required by the target, 637 (eg, append @nn to windows32 stdcall function names). 638 The default is to return ID without modification. */ 639 tree (* mangle_decl_assembler_name) (tree decl, tree id); 640 641 /* Do something target-specific to record properties of the DECL into 642 the associated SYMBOL_REF. */ 643 void (* encode_section_info) (tree, rtx, int); 644 645 /* Undo the effects of encode_section_info on the symbol string. */ 646 const char * (* strip_name_encoding) (const char *); 647 648 /* If shift optabs for MODE are known to always truncate the shift count, 649 return the mask that they apply. Return 0 otherwise. */ 650 unsigned HOST_WIDE_INT (* shift_truncation_mask) (enum machine_mode mode); 651 652 /* Return the number of divisions in the given MODE that should be present, 653 so that it is profitable to turn the division into a multiplication by 654 the reciprocal. */ 655 unsigned int (* min_divisions_for_recip_mul) (enum machine_mode mode); 656 657 /* If the representation of integral MODE is such that values are 658 always sign-extended to a wider mode MODE_REP then return 659 SIGN_EXTEND. Return UNKNOWN otherwise. */ 660 /* Note that the return type ought to be RTX_CODE, but that's not 661 necessarily defined at this point. */ 662 int (* mode_rep_extended) (enum machine_mode mode, 663 enum machine_mode mode_rep); 664 665 /* True if MODE is valid for a pointer in __attribute__((mode("MODE"))). */ 666 bool (* valid_pointer_mode) (enum machine_mode mode); 667 668 /* True if MODE is valid for the target. By "valid", we mean able to 669 be manipulated in non-trivial ways. In particular, this means all 670 the arithmetic is supported. */ 671 bool (* scalar_mode_supported_p) (enum machine_mode mode); 672 673 /* Similarly for vector modes. "Supported" here is less strict. At 674 least some operations are supported; need to check optabs or builtins 675 for further details. */ 676 bool (* vector_mode_supported_p) (enum machine_mode mode); 677 678 /* True if a vector is opaque. */ 679 bool (* vector_opaque_p) (const_tree); 680 681 /* Compute a (partial) cost for rtx X. Return true if the complete 682 cost has been computed, and false if subexpressions should be 683 scanned. In either case, *TOTAL contains the cost result. */ 684 /* Note that CODE and OUTER_CODE ought to be RTX_CODE, but that's 685 not necessarily defined at this point. */ 686 bool (* rtx_costs) (rtx x, int code, int outer_code, int *total, bool speed); 687 688 /* Compute the cost of X, used as an address. Never called with 689 invalid addresses. */ 690 int (* address_cost) (rtx x, bool speed); 691 692 /* Return where to allocate pseudo for a given hard register initial 693 value. */ 694 rtx (* allocate_initial_value) (rtx x); 695 696 /* Return nonzero if evaluating UNSPEC[_VOLATILE] X might cause a trap. 697 FLAGS has the same meaning as in rtlanal.c: may_trap_p_1. */ 698 int (* unspec_may_trap_p) (const_rtx x, unsigned flags); 699 700 /* Given a register, this hook should return a parallel of registers 701 to represent where to find the register pieces. Define this hook 702 if the register and its mode are represented in Dwarf in 703 non-contiguous locations, or if the register should be 704 represented in more than one register in Dwarf. Otherwise, this 705 hook should return NULL_RTX. */ 706 rtx (* dwarf_register_span) (rtx); 707 708 /* If expand_builtin_init_dwarf_reg_sizes needs to fill in table 709 entries not corresponding directly to registers below 710 FIRST_PSEUDO_REGISTER, this hook should generate the necessary 711 code, given the address of the table. */ 712 void (* init_dwarf_reg_sizes_extra) (tree); 713 714 /* Fetch the fixed register(s) which hold condition codes, for 715 targets where it makes sense to look for duplicate assignments to 716 the condition codes. This should return true if there is such a 717 register, false otherwise. The arguments should be set to the 718 fixed register numbers. Up to two condition code registers are 719 supported. If there is only one for this target, the int pointed 720 at by the second argument should be set to -1. */ 721 bool (* fixed_condition_code_regs) (unsigned int *, unsigned int *); 722 723 /* If two condition code modes are compatible, return a condition 724 code mode which is compatible with both, such that a comparison 725 done in the returned mode will work for both of the original 726 modes. If the condition code modes are not compatible, return 727 VOIDmode. */ 728 enum machine_mode (* cc_modes_compatible) (enum machine_mode, 729 enum machine_mode); 730 731 /* Do machine-dependent code transformations. Called just before 732 delayed-branch scheduling. */ 733 void (* machine_dependent_reorg) (void); 734 735 /* Create the __builtin_va_list type. */ 736 tree (* build_builtin_va_list) (void); 737 738 /* Get the cfun/fndecl calling abi __builtin_va_list type. */ 739 tree (* fn_abi_va_list) (tree); 740 741 /* Get the __builtin_va_list type dependent on input type. */ 742 tree (* canonical_va_list_type) (tree); 743 744 /* Expand the __builtin_va_start builtin. */ 745 void (* expand_builtin_va_start) (tree valist, rtx nextarg); 746 747 /* Gimplifies a VA_ARG_EXPR. */ 748 tree (* gimplify_va_arg_expr) (tree valist, tree type, gimple_seq *pre_p, 749 gimple_seq *post_p); 750 751 /* Validity-checking routines for PCH files, target-specific. 752 get_pch_validity returns a pointer to the data to be stored, 753 and stores the size in its argument. pch_valid_p gets the same 754 information back and returns NULL if the PCH is valid, 755 or an error message if not. 756 */ 757 void * (* get_pch_validity) (size_t *); 758 const char * (* pch_valid_p) (const void *, size_t); 759 760 /* If nonnull, this function checks whether a PCH file with the 761 given set of target flags can be used. It returns NULL if so, 762 otherwise it returns an error message. */ 763 const char *(*check_pch_target_flags) (int); 764 765 /* True if the compiler should give an enum type only as many 766 bytes as it takes to represent the range of possible values of 767 that type. */ 768 bool (* default_short_enums) (void); 769 770 /* This target hook returns an rtx that is used to store the address 771 of the current frame into the built-in setjmp buffer. */ 772 rtx (* builtin_setjmp_frame_value) (void); 773 774 /* This target hook should add STRING_CST trees for any hard regs 775 the port wishes to automatically clobber for an asm. */ 776 tree (* md_asm_clobbers) (tree, tree, tree); 777 778 /* This target hook allows the backend to specify a calling convention 779 in the debug information. This function actually returns an 780 enum dwarf_calling_convention, but because of forward declarations 781 and not wanting to include dwarf2.h everywhere target.h is included 782 the function is being declared as an int. */ 783 int (* dwarf_calling_convention) (const_tree); 784 785 /* This target hook allows the backend to emit frame-related insns that 786 contain UNSPECs or UNSPEC_VOLATILEs. The call frame debugging info 787 engine will invoke it on insns of the form 788 (set (reg) (unspec [...] UNSPEC_INDEX)) 789 and 790 (set (reg) (unspec_volatile [...] UNSPECV_INDEX)) 791 to let the backend emit the call frame instructions. */ 792 void (* dwarf_handle_frame_unspec) (const char *, rtx, int); 793 794 /* Perform architecture specific checking of statements gimplified 795 from VA_ARG_EXPR. STMT is the statement. Returns true if the statement 796 doesn't need to be checked for va_list references. */ 797 bool (* stdarg_optimize_hook) (struct stdarg_info *ai, const_gimple stmt); 798 799 /* This target hook allows the operating system to override the DECL 800 that represents the external variable that contains the stack 801 protection guard variable. The type of this DECL is ptr_type_node. */ 802 tree (* stack_protect_guard) (void); 803 804 /* This target hook allows the operating system to override the CALL_EXPR 805 that is invoked when a check vs the guard variable fails. */ 806 tree (* stack_protect_fail) (void); 807 808 /* Returns NULL if target supports the insn within a doloop block, 809 otherwise it returns an error message. */ 810 const char * (*invalid_within_doloop) (const_rtx); 811 812 /* DECL is a variable or function with __attribute__((dllimport)) 813 specified. Use this hook if the target needs to add extra validation 814 checks to handle_dll_attribute (). */ 815 bool (* valid_dllimport_attribute_p) (const_tree decl); 816 817 /* Functions relating to calls - argument passing, returns, etc. */ 818 struct calls { 819 bool (*promote_function_args) (const_tree fntype); 820 bool (*promote_function_return) (const_tree fntype); 821 bool (*promote_prototypes) (const_tree fntype); 822 rtx (*struct_value_rtx) (tree fndecl, int incoming); 823 bool (*return_in_memory) (const_tree type, const_tree fndecl); 824 bool (*return_in_msb) (const_tree type); 825 826 /* Return true if a parameter must be passed by reference. TYPE may 827 be null if this is a libcall. CA may be null if this query is 828 from __builtin_va_arg. */ 829 bool (*pass_by_reference) (CUMULATIVE_ARGS *ca, enum machine_mode mode, 830 const_tree type, bool named_arg); 831 832 rtx (*expand_builtin_saveregs) (void); 833 /* Returns pretend_argument_size. */ 834 void (*setup_incoming_varargs) (CUMULATIVE_ARGS *ca, enum machine_mode mode, 835 tree type, int *pretend_arg_size, 836 int second_time); 837 bool (*strict_argument_naming) (CUMULATIVE_ARGS *ca); 838 /* Returns true if we should use 839 targetm.calls.setup_incoming_varargs() and/or 840 targetm.calls.strict_argument_naming(). */ 841 bool (*pretend_outgoing_varargs_named) (CUMULATIVE_ARGS *ca); 842 843 /* Given a complex type T, return true if a parameter of type T 844 should be passed as two scalars. */ 845 bool (* split_complex_arg) (const_tree type); 846 847 /* Return true if type T, mode MODE, may not be passed in registers, 848 but must be passed on the stack. */ 849 /* ??? This predicate should be applied strictly after pass-by-reference. 850 Need audit to verify that this is the case. */ 851 bool (* must_pass_in_stack) (enum machine_mode mode, const_tree t); 852 853 /* Return true if type TYPE, mode MODE, which is passed by reference, 854 should have the object copy generated by the callee rather than 855 the caller. It is never called for TYPE requiring constructors. */ 856 bool (* callee_copies) (CUMULATIVE_ARGS *ca, enum machine_mode mode, 857 const_tree type, bool named); 858 859 /* Return zero for arguments passed entirely on the stack or entirely 860 in registers. If passed in both, return the number of bytes passed 861 in registers; the balance is therefore passed on the stack. */ 862 int (* arg_partial_bytes) (CUMULATIVE_ARGS *ca, enum machine_mode mode, 863 tree type, bool named); 864 865 /* Return the diagnostic message string if function without a prototype 866 is not allowed for this 'val' argument; NULL otherwise. */ 867 const char *(*invalid_arg_for_unprototyped_fn) (const_tree typelist, 868 const_tree funcdecl, 869 const_tree val); 870 871 /* Return an rtx for the return value location of the function 872 specified by FN_DECL_OR_TYPE with a return type of RET_TYPE. */ 873 rtx (*function_value) (const_tree ret_type, const_tree fn_decl_or_type, 874 bool outgoing); 875 876 /* Return an rtx for the argument pointer incoming to the 877 current function. */ 878 rtx (*internal_arg_pointer) (void); 879 880 /* Update the current function stack boundary if needed. */ 881 void (*update_stack_boundary) (void); 882 883 /* Handle stack alignment and return an rtx for Dynamic Realign 884 Argument Pointer if necessary. */ 885 rtx (*get_drap_rtx) (void); 886 887 /* Return true if all function parameters should be spilled to the 888 stack. */ 889 bool (*allocate_stack_slots_for_args) (void); 890 891 } calls; 892 893 /* Return the diagnostic message string if conversion from FROMTYPE 894 to TOTYPE is not allowed, NULL otherwise. */ 895 const char *(*invalid_conversion) (const_tree fromtype, const_tree totype); 896 897 /* Return the diagnostic message string if the unary operation OP is 898 not permitted on TYPE, NULL otherwise. */ 899 const char *(*invalid_unary_op) (int op, const_tree type); 900 901 /* Return the diagnostic message string if the binary operation OP 902 is not permitted on TYPE1 and TYPE2, NULL otherwise. */ 903 const char *(*invalid_binary_op) (int op, const_tree type1, const_tree type2); 904 905 /* Return the array of IRA cover classes for the current target. */ 906 const enum reg_class *(*ira_cover_classes) (void); 907 908 /* Return the class for a secondary reload, and fill in extra information. */ 909 enum reg_class (*secondary_reload) (bool, rtx, enum reg_class, 910 enum machine_mode, 911 struct secondary_reload_info *); 912 913 /* This target hook allows the backend to perform additional 914 processing while initializing for variable expansion. */ 915 void (* expand_to_rtl_hook) (void); 916 917 /* This target hook allows the backend to perform additional 918 instantiations on rtx that are not actually in insns yet, 919 but will be later. */ 920 void (* instantiate_decls) (void); 921 922 /* Return true if is OK to use a hard register REGNO as scratch register 923 in peephole2. */ 924 bool (* hard_regno_scratch_ok) (unsigned int regno); 925 926 /* Functions specific to the C family of frontends. */ 927 struct c { 928 /* Return machine mode for non-standard suffix 929 or VOIDmode if non-standard suffixes are unsupported. */ 930 enum machine_mode (*mode_for_suffix) (char); 931 } c; 932 933 /* Functions specific to the C++ frontend. */ 934 struct cxx { 935 /* Return the integer type used for guard variables. */ 936 tree (*guard_type) (void); 937 /* Return true if only the low bit of the guard should be tested. */ 938 bool (*guard_mask_bit) (void); 939 /* Returns the size of the array cookie for an array of type. */ 940 tree (*get_cookie_size) (tree); 941 /* Returns true if the element size should be stored in the 942 array cookie. */ 943 bool (*cookie_has_size) (void); 944 /* Allows backends to perform additional processing when 945 deciding if a class should be exported or imported. */ 946 int (*import_export_class) (tree, int); 947 /* Returns true if constructors and destructors return "this". */ 948 bool (*cdtor_returns_this) (void); 949 /* Returns true if the key method for a class can be an inline 950 function, so long as it is not declared inline in the class 951 itself. Returning true is the behavior required by the Itanium 952 C++ ABI. */ 953 bool (*key_method_may_be_inline) (void); 954 /* DECL is a virtual table, virtual table table, typeinfo object, 955 or other similar implicit class data object that will be 956 emitted with external linkage in this translation unit. No ELF 957 visibility has been explicitly specified. If the target needs 958 to specify a visibility other than that of the containing class, 959 use this hook to set DECL_VISIBILITY and 960 DECL_VISIBILITY_SPECIFIED. */ 961 void (*determine_class_data_visibility) (tree decl); 962 /* Returns true (the default) if virtual tables and other 963 similar implicit class data objects are always COMDAT if they 964 have external linkage. If this hook returns false, then 965 class data for classes whose virtual table will be emitted in 966 only one translation unit will not be COMDAT. */ 967 bool (*class_data_always_comdat) (void); 968 /* Returns true (the default) if the RTTI for the basic types, 969 which is always defined in the C++ runtime, should be COMDAT; 970 false if it should not be COMDAT. */ 971 bool (*library_rtti_comdat) (void); 972 /* Returns true if __aeabi_atexit should be used to register static 973 destructors. */ 974 bool (*use_aeabi_atexit) (void); 975 /* Returns true if target may use atexit in the same manner as 976 __cxa_atexit to register static destructors. */ 977 bool (*use_atexit_for_cxa_atexit) (void); 978 /* TYPE is a C++ class (i.e., RECORD_TYPE or UNION_TYPE) that 979 has just been defined. Use this hook to make adjustments to the 980 class (eg, tweak visibility or perform any other required 981 target modifications). */ 982 void (*adjust_class_at_definition) (tree type); 983 } cxx; 984 985 /* Functions and data for emulated TLS support. */ 986 struct emutls { 987 /* Name of the address and common functions. */ 988 const char *get_address; 989 const char *register_common; 990 991 /* Prefixes for proxy variable and template. */ 992 const char *var_section; 993 const char *tmpl_section; 994 995 /* Prefixes for proxy variable and template. */ 996 const char *var_prefix; 997 const char *tmpl_prefix; 998 999 /* Function to generate field definitions of the proxy variable. */ 1000 tree (*var_fields) (tree, tree *); 1001 1002 /* Function to initialize a proxy variable. */ 1003 tree (*var_init) (tree, tree, tree); 1004 1005 /* Whether we are allowed to alter the usual alignment of the 1006 proxy variable. */ 1007 bool var_align_fixed; 1008 1009 /* Whether we can emit debug information for TLS vars. */ 1010 bool debug_form_tls_address; 1011 } emutls; 1012 1013 struct target_option_hooks { 1014 /* Function to validate the attribute((option(...))) strings or NULL. If 1015 the option is validated, it is assumed that DECL_FUNCTION_SPECIFIC will 1016 be filled in in the function decl node. */ 1017 bool (*valid_attribute_p) (tree, tree, tree, int); 1018 1019 /* Function to save any extra target state in the target options 1020 structure. */ 1021 void (*save) (struct cl_target_option *); 1022 1023 /* Function to restore any extra target state from the target options 1024 structure. */ 1025 void (*restore) (struct cl_target_option *); 1026 1027 /* Function to print any extra target state from the target options 1028 structure. */ 1029 void (*print) (FILE *, int, struct cl_target_option *); 1030 1031 /* Function to parse arguments to be validated for #pragma option, and to 1032 change the state if the options are valid. If the first argument is 1033 NULL, the second argument specifies the default options to use. Return 1034 true if the options are valid, and set the current state. */ 1035 bool (*pragma_parse) (tree, tree); 1036 1037 /* Function to determine if one function can inline another function. */ 1038 bool (*can_inline_p) (tree, tree); 1039 } target_option; 1040 1041 /* Functions used to simplify GOT access. */ 1042 struct simplify_got_access { 1043 /* Function to get the pic_reg which holds the base address of GOT. */ 1044 rtx (*get_pic_reg) (void); 1045 1046 /* Function to clear the pic_reg which is useless now. */ 1047 void (*clear_pic_reg) (void); 1048 1049 /* Function to detect if the specified insn loads a global variable's 1050 address from GOT. If so returns that symbol. */ 1051 rtx (*loaded_global_var) (rtx, rtx *); 1052 1053 /* This function checks if it satisfy the target dependent conditions 1054 that we can simplify GOT accesses. */ 1055 bool (*can_simplify_got_access) (int, int); 1056 1057 /* This function does the actual rewriting of GOT accesses. */ 1058 void (*load_global_address) (rtx, rtx, rtx, rtx); 1059 } got_access; 1060 1061 /* For targets that need to mark extra registers as live on entry to 1062 the function, they should define this target hook and set their 1063 bits in the bitmap passed in. */ 1064 void (*live_on_entry) (bitmap); 1065 1066 /* True if unwinding tables should be generated by default. */ 1067 bool unwind_tables_default; 1068 1069 /* Leave the boolean fields at the end. */ 1070 1071 /* True if arbitrary sections are supported. */ 1072 bool have_named_sections; 1073 1074 /* True if we can create zeroed data by switching to a BSS section 1075 and then using ASM_OUTPUT_SKIP to allocate the space. */ 1076 bool have_switchable_bss_sections; 1077 1078 /* True if "native" constructors and destructors are supported, 1079 false if we're using collect2 for the job. */ 1080 bool have_ctors_dtors; 1081 1082 /* True if thread-local storage is supported. */ 1083 bool have_tls; 1084 1085 /* True if a small readonly data section is supported. */ 1086 bool have_srodata_section; 1087 1088 /* True if EH frame info sections should be zero-terminated. */ 1089 bool terminate_dw2_eh_frame_info; 1090 1091 /* True if #NO_APP should be emitted at the beginning of 1092 assembly output. */ 1093 bool file_start_app_off; 1094 1095 /* True if output_file_directive should be called for main_input_filename 1096 at the beginning of assembly output. */ 1097 bool file_start_file_directive; 1098 1099 /* True if #pragma redefine_extname is to be supported. */ 1100 bool handle_pragma_redefine_extname; 1101 1102 /* True if #pragma extern_prefix is to be supported. */ 1103 bool handle_pragma_extern_prefix; 1104 1105 /* True if the target is allowed to reorder memory accesses unless 1106 synchronization is explicitly requested. */ 1107 bool relaxed_ordering; 1108 1109 /* Returns true if we should generate exception tables for use with the 1110 ARM EABI. The effects the encoding of function exception specifications. 1111 */ 1112 bool arm_eabi_unwinder; 1113 1114 /* Leave the boolean fields at the end. */ 1115 }; 1116 1117 extern struct gcc_target targetm; 1118 1119 struct gcc_targetcm { 1120 /* Handle target switch CODE (an OPT_* value). ARG is the argument 1121 passed to the switch; it is NULL if no argument was. VALUE is the 1122 value of ARG if CODE specifies a UInteger option, otherwise it is 1123 1 if the positive form of the switch was used and 0 if the negative 1124 form was. Return true if the switch was valid. */ 1125 bool (*handle_c_option) (size_t code, const char *arg, int value); 1126 }; 1127 1128 /* Each target can provide their own. */ 1129 extern struct gcc_targetcm targetcm; 1130 1131 #endif /* GCC_TARGET_H */ 1132
