1 /* Data structure definitions for a generic GCC target. 2 Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007 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 2, 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; if not, write to the Free Software 17 Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. 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 /* This file contains a data structure that describes a GCC target. 24 At present it is incomplete, but in future it should grow to 25 contain most or all target machine and target O/S specific 26 information. 27 28 This structure has its initializer declared in target-def.h in the 29 form of large macro TARGET_INITIALIZER that expands to many smaller 30 macros. 31 32 The smaller macros each initialize one component of the structure, 33 and each has a default. Each target should have a file that 34 includes target.h and target-def.h, and overrides any inappropriate 35 defaults by undefining the relevant macro and defining a suitable 36 replacement. That file should then contain the definition of 37 "targetm" like so: 38 39 struct gcc_target targetm = TARGET_INITIALIZER; 40 41 Doing things this way allows us to bring together everything that 42 defines a GCC target. By supplying a default that is appropriate 43 to most targets, we can easily add new items without needing to 44 edit dozens of target configuration files. It should also allow us 45 to gradually reduce the amount of conditional compilation that is 46 scattered throughout GCC. */ 47 48 #ifndef GCC_TARGET_H 49 #define GCC_TARGET_H 50 51 #include "tm.h" 52 #include "insn-modes.h" 53 54 struct stdarg_info; 55 struct spec_info_def; 56 57 /* The struct used by the secondary_reload target hook. */ 58 typedef struct secondary_reload_info 59 { 60 /* icode is actually an enum insn_code, but we don't want to force every 61 file that includes target.h to include optabs.h . */ 62 int icode; 63 int extra_cost; /* Cost for using (a) scratch register(s) to be taken 64 into account by copy_cost. */ 65 /* The next two members are for the use of the backward 66 compatibility hook. */ 67 struct secondary_reload_info *prev_sri; 68 int t_icode; /* Actually an enum insn_code - see above. */ 69 } secondary_reload_info; 70 71 72 struct gcc_target 73 { 74 /* Functions that output assembler for the target. */ 75 struct asm_out 76 { 77 /* Opening and closing parentheses for asm expression grouping. */ 78 const char *open_paren, *close_paren; 79 80 /* Assembler instructions for creating various kinds of integer object. */ 81 const char *byte_op; 82 struct asm_int_op 83 { 84 const char *hi; 85 const char *si; 86 const char *di; 87 const char *ti; 88 } aligned_op, unaligned_op; 89 90 /* Try to output the assembler code for an integer object whose 91 value is given by X. SIZE is the size of the object in bytes and 92 ALIGNED_P indicates whether it is aligned. Return true if 93 successful. Only handles cases for which BYTE_OP, ALIGNED_OP 94 and UNALIGNED_OP are NULL. */ 95 bool (* integer) (rtx x, unsigned int size, int aligned_p); 96 97 /* Output code that will globalize a label. */ 98 void (* globalize_label) (FILE *, const char *); 99 100 /* Output code that will emit a label for unwind info, if this 101 target requires such labels. Second argument is the decl the 102 unwind info is associated with, third is a boolean: true if 103 this is for exception handling, fourth is a boolean: true if 104 this is only a placeholder for an omitted FDE. */ 105 void (* unwind_label) (FILE *, tree, int, int); 106 107 /* Output code that will emit a label to divide up the exception 108 table. */ 109 void (* except_table_label) (FILE *); 110 111 /* Emit any directives required to unwind this instruction. */ 112 void (* unwind_emit) (FILE *, rtx); 113 114 /* Output an internal label. */ 115 void (* internal_label) (FILE *, const char *, unsigned long); 116 117 /* Emit a ttype table reference to a typeinfo object. */ 118 bool (* ttype) (rtx); 119 120 /* Emit an assembler directive to set visibility for the symbol 121 associated with the tree decl. */ 122 void (* visibility) (tree, int); 123 124 /* Output the assembler code for entry to a function. */ 125 void (* function_prologue) (FILE *, HOST_WIDE_INT); 126 127 /* Output the assembler code for end of prologue. */ 128 void (* function_end_prologue) (FILE *); 129 130 /* Output the assembler code for start of epilogue. */ 131 void (* function_begin_epilogue) (FILE *); 132 133 /* Output the assembler code for function exit. */ 134 void (* function_epilogue) (FILE *, HOST_WIDE_INT); 135 136 /* Initialize target-specific sections. */ 137 void (* init_sections) (void); 138 139 /* Tell assembler to change to section NAME with attributes FLAGS. 140 If DECL is non-NULL, it is the VAR_DECL or FUNCTION_DECL with 141 which this section is associated. */ 142 void (* named_section) (const char *name, unsigned int flags, tree decl); 143 144 /* Return a mask describing how relocations should be treated when 145 selecting sections. Bit 1 should be set if global relocations 146 should be placed in a read-write section; bit 0 should be set if 147 local relocations should be placed in a read-write section. */ 148 int (*reloc_rw_mask) (void); 149 150 /* Return a section for EXP. It may be a DECL or a constant. RELOC 151 is nonzero if runtime relocations must be applied; bit 1 will be 152 set if the runtime relocations require non-local name resolution. 153 ALIGN is the required alignment of the data. */ 154 section *(* select_section) (tree, int, unsigned HOST_WIDE_INT); 155 156 /* Return a section for X. MODE is X's mode and ALIGN is its 157 alignment in bits. */ 158 section *(* select_rtx_section) (enum machine_mode, rtx, 159 unsigned HOST_WIDE_INT); 160 161 /* Select a unique section name for DECL. RELOC is the same as 162 for SELECT_SECTION. */ 163 void (* unique_section) (tree, int); 164 165 /* Return the readonly data section associated with function DECL. */ 166 section *(* function_rodata_section) (tree); 167 168 /* Output a constructor for a symbol with a given priority. */ 169 void (* constructor) (rtx, int); 170 171 /* Output a destructor for a symbol with a given priority. */ 172 void (* destructor) (rtx, int); 173 174 /* Output the assembler code for a thunk function. THUNK_DECL is the 175 declaration for the thunk function itself, FUNCTION is the decl for 176 the target function. DELTA is an immediate constant offset to be 177 added to THIS. If VCALL_OFFSET is nonzero, the word at 178 *(*this + vcall_offset) should be added to THIS. */ 179 void (* output_mi_thunk) (FILE *file, tree thunk_decl, 180 HOST_WIDE_INT delta, HOST_WIDE_INT vcall_offset, 181 tree function_decl); 182 183 /* Determine whether output_mi_thunk would succeed. */ 184 /* ??? Ideally, this hook would not exist, and success or failure 185 would be returned from output_mi_thunk directly. But there's 186 too much undo-able setup involved in invoking output_mi_thunk. 187 Could be fixed by making output_mi_thunk emit rtl instead of 188 text to the output file. */ 189 bool (* can_output_mi_thunk) (tree thunk_decl, HOST_WIDE_INT delta, 190 HOST_WIDE_INT vcall_offset, 191 tree function_decl); 192 193 /* Output any boilerplate text needed at the beginning of a 194 translation unit. */ 195 void (*file_start) (void); 196 197 /* Output any boilerplate text needed at the end of a 198 translation unit. */ 199 void (*file_end) (void); 200 201 /* Output an assembler pseudo-op to declare a library function name 202 external. */ 203 void (*external_libcall) (rtx); 204 205 /* Output an assembler directive to mark decl live. This instructs 206 linker to not dead code strip this symbol. */ 207 void (*mark_decl_preserved) (const char *); 208 209 /* Output the definition of a section anchor. */ 210 void (*output_anchor) (rtx); 211 212 /* Output a DTP-relative reference to a TLS symbol. */ 213 void (*output_dwarf_dtprel) (FILE *file, int size, rtx x); 214 215 } asm_out; 216 217 /* Functions relating to instruction scheduling. */ 218 struct sched 219 { 220 /* Given the current cost, COST, of an insn, INSN, calculate and 221 return a new cost based on its relationship to DEP_INSN through 222 the dependence LINK. The default is to make no adjustment. */ 223 int (* adjust_cost) (rtx insn, rtx link, rtx def_insn, int cost); 224 225 /* Adjust the priority of an insn as you see fit. Returns the new 226 priority. */ 227 int (* adjust_priority) (rtx, int); 228 229 /* Function which returns the maximum number of insns that can be 230 scheduled in the same machine cycle. This must be constant 231 over an entire compilation. The default is 1. */ 232 int (* issue_rate) (void); 233 234 /* Calculate how much this insn affects how many more insns we 235 can emit this cycle. Default is they all cost the same. */ 236 int (* variable_issue) (FILE *, int, rtx, int); 237 238 /* Initialize machine-dependent scheduling code. */ 239 void (* md_init) (FILE *, int, int); 240 241 /* Finalize machine-dependent scheduling code. */ 242 void (* md_finish) (FILE *, int); 243 244 /* Initialize machine-dependent function while scheduling code. */ 245 void (* md_init_global) (FILE *, int, int); 246 247 /* Finalize machine-dependent function wide scheduling code. */ 248 void (* md_finish_global) (FILE *, int); 249 250 /* Reorder insns in a machine-dependent fashion, in two different 251 places. Default does nothing. */ 252 int (* reorder) (FILE *, int, rtx *, int *, int); 253 int (* reorder2) (FILE *, int, rtx *, int *, int); 254 255 /* The following member value is a pointer to a function called 256 after evaluation forward dependencies of insns in chain given 257 by two parameter values (head and tail correspondingly). */ 258 void (* dependencies_evaluation_hook) (rtx, rtx); 259 260 /* The values of the following four members are pointers to 261 functions used to simplify the automaton descriptions. 262 dfa_pre_cycle_insn and dfa_post_cycle_insn give functions 263 returning insns which are used to change the pipeline hazard 264 recognizer state when the new simulated processor cycle 265 correspondingly starts and finishes. The function defined by 266 init_dfa_pre_cycle_insn and init_dfa_post_cycle_insn are used 267 to initialize the corresponding insns. The default values of 268 the members result in not changing the automaton state when 269 the new simulated processor cycle correspondingly starts and 270 finishes. */ 271 void (* init_dfa_pre_cycle_insn) (void); 272 rtx (* dfa_pre_cycle_insn) (void); 273 void (* init_dfa_post_cycle_insn) (void); 274 rtx (* dfa_post_cycle_insn) (void); 275 276 /* The following member value is a pointer to a function returning value 277 which defines how many insns in queue `ready' will we try for 278 multi-pass scheduling. If the member value is nonzero and the 279 function returns positive value, the DFA based scheduler will make 280 multi-pass scheduling for the first cycle. In other words, we will 281 try to choose ready insn which permits to start maximum number of 282 insns on the same cycle. */ 283 int (* first_cycle_multipass_dfa_lookahead) (void); 284 285 /* The following member value is pointer to a function controlling 286 what insns from the ready insn queue will be considered for the 287 multipass insn scheduling. If the hook returns zero for insn 288 passed as the parameter, the insn will be not chosen to be 289 issued. */ 290 int (* first_cycle_multipass_dfa_lookahead_guard) (rtx); 291 292 /* The following member value is pointer to a function called by 293 the insn scheduler before issuing insn passed as the third 294 parameter on given cycle. If the hook returns nonzero, the 295 insn is not issued on given processors cycle. Instead of that, 296 the processor cycle is advanced. If the value passed through 297 the last parameter is zero, the insn ready queue is not sorted 298 on the new cycle start as usually. The first parameter passes 299 file for debugging output. The second one passes the scheduler 300 verbose level of the debugging output. The forth and the fifth 301 parameter values are correspondingly processor cycle on which 302 the previous insn has been issued and the current processor 303 cycle. */ 304 int (* dfa_new_cycle) (FILE *, int, rtx, int, int, int *); 305 306 /* The following member value is a pointer to a function called 307 by the insn scheduler. It should return true if there exists a 308 dependence which is considered costly by the target, between 309 the insn passed as the first parameter, and the insn passed as 310 the second parameter. The third parameter is the INSN_DEPEND 311 link that represents the dependence between the two insns. The 312 fourth argument is the cost of the dependence as estimated by 313 the scheduler. The last argument is the distance in cycles 314 between the already scheduled insn (first parameter) and the 315 the second insn (second parameter). */ 316 bool (* is_costly_dependence) (rtx, rtx, rtx, int, int); 317 318 /* Given the current cost, COST, of an insn, INSN, calculate and 319 return a new cost based on its relationship to DEP_INSN through the 320 dependence of type DEP_TYPE. The default is to make no adjustment. */ 321 int (* adjust_cost_2) (rtx insn, int, rtx def_insn, int cost); 322 323 /* The following member value is a pointer to a function called 324 by the insn scheduler. This hook is called to notify the backend 325 that new instructions were emitted. */ 326 void (* h_i_d_extended) (void); 327 328 /* The following member value is a pointer to a function called 329 by the insn scheduler. 330 The first parameter is an instruction, the second parameter is the type 331 of the requested speculation, and the third parameter is a pointer to the 332 speculative pattern of the corresponding type (set if return value == 1). 333 It should return 334 -1, if there is no pattern, that will satisfy the requested speculation 335 type, 336 0, if current pattern satisfies the requested speculation type, 337 1, if pattern of the instruction should be changed to the newly 338 generated one. */ 339 int (* speculate_insn) (rtx, int, rtx *); 340 341 /* The following member value is a pointer to a function called 342 by the insn scheduler. It should return true if the check instruction 343 corresponding to the instruction passed as the parameter needs a 344 recovery block. */ 345 bool (* needs_block_p) (rtx); 346 347 /* The following member value is a pointer to a function called 348 by the insn scheduler. It should return a pattern for the check 349 instruction. 350 The first parameter is a speculative instruction, the second parameter 351 is the label of the corresponding recovery block (or null, if it is a 352 simple check). If the mutation of the check is requested (e.g. from 353 ld.c to chk.a), the third parameter is true - in this case the first 354 parameter is the previous check. */ 355 rtx (* gen_check) (rtx, rtx, bool); 356 357 /* The following member value is a pointer to a function controlling 358 what insns from the ready insn queue will be considered for the 359 multipass insn scheduling. If the hook returns zero for the insn 360 passed as the parameter, the insn will not be chosen to be 361 issued. This hook is used to discard speculative instructions, 362 that stand at the first position of the ready list. */ 363 bool (* first_cycle_multipass_dfa_lookahead_guard_spec) (rtx); 364 365 /* The following member value is a pointer to a function that provides 366 information about the speculation capabilities of the target. 367 The parameter is a pointer to spec_info variable. */ 368 void (* set_sched_flags) (struct spec_info_def *); 369 } sched; 370 371 /* Functions relating to vectorization. */ 372 struct vectorize 373 { 374 /* The following member value is a pointer to a function called 375 by the vectorizer, and return the decl of the target builtin 376 function. */ 377 tree (* builtin_mask_for_load) (void); 378 379 /* Return true if vector alignment is reachable (by peeling N 380 interations) for the given type. */ 381 bool (* vector_alignment_reachable) (tree, bool); 382 } vectorize; 383 384 /* The initial value of target_flags. */ 385 int default_target_flags; 386 387 /* Handle target switch CODE (an OPT_* value). ARG is the argument 388 passed to the switch; it is NULL if no argument was. VALUE is the 389 value of ARG if CODE specifies a UInteger option, otherwise it is 390 1 if the positive form of the switch was used and 0 if the negative 391 form was. Return true if the switch was valid. */ 392 bool (* handle_option) (size_t code, const char *arg, int value); 393 394 /* Return machine mode for filter value. */ 395 enum machine_mode (* eh_return_filter_mode) (void); 396 397 /* Given two decls, merge their attributes and return the result. */ 398 tree (* merge_decl_attributes) (tree, tree); 399 400 /* Given two types, merge their attributes and return the result. */ 401 tree (* merge_type_attributes) (tree, tree); 402 403 /* Table of machine attributes and functions to handle them. 404 Ignored if NULL. */ 405 const struct attribute_spec *attribute_table; 406 407 /* Return zero if the attributes on TYPE1 and TYPE2 are incompatible, 408 one if they are compatible and two if they are nearly compatible 409 (which causes a warning to be generated). */ 410 int (* comp_type_attributes) (tree type1, tree type2); 411 412 /* Assign default attributes to the newly defined TYPE. */ 413 void (* set_default_type_attributes) (tree type); 414 415 /* Insert attributes on the newly created DECL. */ 416 void (* insert_attributes) (tree decl, tree *attributes); 417 418 /* Return true if FNDECL (which has at least one machine attribute) 419 can be inlined despite its machine attributes, false otherwise. */ 420 bool (* function_attribute_inlinable_p) (tree fndecl); 421 422 /* Return true if bitfields in RECORD_TYPE should follow the 423 Microsoft Visual C++ bitfield layout rules. */ 424 bool (* ms_bitfield_layout_p) (tree record_type); 425 426 /* True if the target supports decimal floating point. */ 427 bool (* decimal_float_supported_p) (void); 428 429 /* Return true if anonymous bitfields affect structure alignment. */ 430 bool (* align_anon_bitfield) (void); 431 432 /* Return true if volatile bitfields should use the narrowest type possible. 433 Return false if they should use the container type. */ 434 bool (* narrow_volatile_bitfield) (void); 435 436 /* Set up target-specific built-in functions. */ 437 void (* init_builtins) (void); 438 439 /* Expand a target-specific builtin. */ 440 rtx (* expand_builtin) (tree exp, rtx target, rtx subtarget, 441 enum machine_mode mode, int ignore); 442 443 /* Select a replacement for a target-specific builtin. This is done 444 *before* regular type checking, and so allows the target to implement 445 a crude form of function overloading. The result is a complete 446 expression that implements the operation. */ 447 tree (*resolve_overloaded_builtin) (tree decl, tree params); 448 449 /* Fold a target-specific builtin. */ 450 tree (* fold_builtin) (tree fndecl, tree arglist, bool ignore); 451 452 /* For a vendor-specific fundamental TYPE, return a pointer to 453 a statically-allocated string containing the C++ mangling for 454 TYPE. In all other cases, return NULL. */ 455 const char * (* mangle_fundamental_type) (tree type); 456 457 /* Make any adjustments to libfunc names needed for this target. */ 458 void (* init_libfuncs) (void); 459 460 /* Given a decl, a section name, and whether the decl initializer 461 has relocs, choose attributes for the section. */ 462 /* ??? Should be merged with SELECT_SECTION and UNIQUE_SECTION. */ 463 unsigned int (* section_type_flags) (tree, const char *, int); 464 465 /* True if new jumps cannot be created, to replace existing ones or 466 not, at the current point in the compilation. */ 467 bool (* cannot_modify_jumps_p) (void); 468 469 /* Return a register class for which branch target register 470 optimizations should be applied. */ 471 int (* branch_target_register_class) (void); 472 473 /* Return true if branch target register optimizations should include 474 callee-saved registers that are not already live during the current 475 function. AFTER_PE_GEN is true if prologues and epilogues have 476 already been generated. */ 477 bool (* branch_target_register_callee_saved) (bool after_pe_gen); 478 479 /* True if the constant X cannot be placed in the constant pool. */ 480 bool (* cannot_force_const_mem) (rtx); 481 482 /* True if the insn X cannot be duplicated. */ 483 bool (* cannot_copy_insn_p) (rtx); 484 485 /* True if X is considered to be commutative. */ 486 bool (* commutative_p) (rtx, int); 487 488 /* Given an address RTX, undo the effects of LEGITIMIZE_ADDRESS. */ 489 rtx (* delegitimize_address) (rtx); 490 491 /* True if the given constant can be put into an object_block. */ 492 bool (* use_blocks_for_constant_p) (enum machine_mode, rtx); 493 494 /* The minimum and maximum byte offsets for anchored addresses. */ 495 HOST_WIDE_INT min_anchor_offset; 496 HOST_WIDE_INT max_anchor_offset; 497 498 /* True if section anchors can be used to access the given symbol. */ 499 bool (* use_anchors_for_symbol_p) (rtx); 500 501 /* True if it is OK to do sibling call optimization for the specified 502 call expression EXP. DECL will be the called function, or NULL if 503 this is an indirect call. */ 504 bool (*function_ok_for_sibcall) (tree decl, tree exp); 505 506 /* True if EXP should be placed in a "small data" section. */ 507 bool (* in_small_data_p) (tree); 508 509 /* True if EXP names an object for which name resolution must resolve 510 to the current module. */ 511 bool (* binds_local_p) (tree); 512 513 /* Do something target-specific to record properties of the DECL into 514 the associated SYMBOL_REF. */ 515 void (* encode_section_info) (tree, rtx, int); 516 517 /* Undo the effects of encode_section_info on the symbol string. */ 518 const char * (* strip_name_encoding) (const char *); 519 520 /* If shift optabs for MODE are known to always truncate the shift count, 521 return the mask that they apply. Return 0 otherwise. */ 522 unsigned HOST_WIDE_INT (* shift_truncation_mask) (enum machine_mode mode); 523 524 /* Return the number of divisions in the given MODE that should be present, 525 so that it is profitable to turn the division into a multiplication by 526 the reciprocal. */ 527 unsigned int (* min_divisions_for_recip_mul) (enum machine_mode mode); 528 529 /* If the representation of integral MODE is such that values are 530 always sign-extended to a wider mode MODE_REP then return 531 SIGN_EXTEND. Return UNKNOWN otherwise. */ 532 /* Note that the return type ought to be RTX_CODE, but that's not 533 necessarily defined at this point. */ 534 int (* mode_rep_extended) (enum machine_mode mode, 535 enum machine_mode mode_rep); 536 537 /* True if MODE is valid for a pointer in __attribute__((mode("MODE"))). */ 538 bool (* valid_pointer_mode) (enum machine_mode mode); 539 540 /* True if MODE is valid for the target. By "valid", we mean able to 541 be manipulated in non-trivial ways. In particular, this means all 542 the arithmetic is supported. */ 543 bool (* scalar_mode_supported_p) (enum machine_mode mode); 544 545 /* Similarly for vector modes. "Supported" here is less strict. At 546 least some operations are supported; need to check optabs or builtins 547 for further details. */ 548 bool (* vector_mode_supported_p) (enum machine_mode mode); 549 550 /* True if a vector is opaque. */ 551 bool (* vector_opaque_p) (tree); 552 553 /* Compute a (partial) cost for rtx X. Return true if the complete 554 cost has been computed, and false if subexpressions should be 555 scanned. In either case, *TOTAL contains the cost result. */ 556 /* Note that CODE and OUTER_CODE ought to be RTX_CODE, but that's 557 not necessarily defined at this point. */ 558 bool (* rtx_costs) (rtx x, int code, int outer_code, int *total); 559 560 /* Compute the cost of X, used as an address. Never called with 561 invalid addresses. */ 562 int (* address_cost) (rtx x); 563 564 /* Return where to allocate pseudo for a given hard register initial 565 value. */ 566 rtx (* allocate_initial_value) (rtx x); 567 568 /* Given a register, this hook should return a parallel of registers 569 to represent where to find the register pieces. Define this hook 570 if the register and its mode are represented in Dwarf in 571 non-contiguous locations, or if the register should be 572 represented in more than one register in Dwarf. Otherwise, this 573 hook should return NULL_RTX. */ 574 rtx (* dwarf_register_span) (rtx); 575 576 /* Fetch the fixed register(s) which hold condition codes, for 577 targets where it makes sense to look for duplicate assignments to 578 the condition codes. This should return true if there is such a 579 register, false otherwise. The arguments should be set to the 580 fixed register numbers. Up to two condition code registers are 581 supported. If there is only one for this target, the int pointed 582 at by the second argument should be set to -1. */ 583 bool (* fixed_condition_code_regs) (unsigned int *, unsigned int *); 584 585 /* If two condition code modes are compatible, return a condition 586 code mode which is compatible with both, such that a comparison 587 done in the returned mode will work for both of the original 588 modes. If the condition code modes are not compatible, return 589 VOIDmode. */ 590 enum machine_mode (* cc_modes_compatible) (enum machine_mode, 591 enum machine_mode); 592 593 /* Do machine-dependent code transformations. Called just before 594 delayed-branch scheduling. */ 595 void (* machine_dependent_reorg) (void); 596 597 /* Create the __builtin_va_list type. */ 598 tree (* build_builtin_va_list) (void); 599 600 /* Gimplifies a VA_ARG_EXPR. */ 601 tree (* gimplify_va_arg_expr) (tree valist, tree type, tree *pre_p, 602 tree *post_p); 603 604 /* Validity-checking routines for PCH files, target-specific. 605 get_pch_validity returns a pointer to the data to be stored, 606 and stores the size in its argument. pch_valid_p gets the same 607 information back and returns NULL if the PCH is valid, 608 or an error message if not. 609 */ 610 void * (* get_pch_validity) (size_t *); 611 const char * (* pch_valid_p) (const void *, size_t); 612 613 /* If nonnull, this function checks whether a PCH file with the 614 given set of target flags can be used. It returns NULL if so, 615 otherwise it returns an error message. */ 616 const char *(*check_pch_target_flags) (int); 617 618 /* True if the compiler should give an enum type only as many 619 bytes as it takes to represent the range of possible values of 620 that type. */ 621 bool (* default_short_enums) (void); 622 623 /* This target hook returns an rtx that is used to store the address 624 of the current frame into the built-in setjmp buffer. */ 625 rtx (* builtin_setjmp_frame_value) (void); 626 627 /* This target hook should add STRING_CST trees for any hard regs 628 the port wishes to automatically clobber for an asm. */ 629 tree (* md_asm_clobbers) (tree, tree, tree); 630 631 /* This target hook allows the backend to specify a calling convention 632 in the debug information. This function actually returns an 633 enum dwarf_calling_convention, but because of forward declarations 634 and not wanting to include dwarf2.h everywhere target.h is included 635 the function is being declared as an int. */ 636 int (* dwarf_calling_convention) (tree); 637 638 /* This target hook allows the backend to emit frame-related insns that 639 contain UNSPECs or UNSPEC_VOLATILEs. The call frame debugging info 640 engine will invoke it on insns of the form 641 (set (reg) (unspec [...] UNSPEC_INDEX)) 642 and 643 (set (reg) (unspec_volatile [...] UNSPECV_INDEX)) 644 to let the backend emit the call frame instructions. */ 645 void (* dwarf_handle_frame_unspec) (const char *, rtx, int); 646 647 /* Perform architecture specific checking of statements gimplified 648 from VA_ARG_EXPR. LHS is left hand side of MODIFY_EXPR, RHS 649 is right hand side. Returns true if the statements doesn't need 650 to be checked for va_list references. */ 651 bool (* stdarg_optimize_hook) (struct stdarg_info *ai, tree lhs, tree rhs); 652 653 /* This target hook allows the operating system to override the DECL 654 that represents the external variable that contains the stack 655 protection guard variable. The type of this DECL is ptr_type_node. */ 656 tree (* stack_protect_guard) (void); 657 658 /* This target hook allows the operating system to override the CALL_EXPR 659 that is invoked when a check vs the guard variable fails. */ 660 tree (* stack_protect_fail) (void); 661 662 /* Returns NULL if target supports the insn within a doloop block, 663 otherwise it returns an error message. */ 664 const char * (*invalid_within_doloop) (rtx); 665 666 /* DECL is a variable or function with __attribute__((dllimport)) 667 specified. Use this hook if the target needs to add extra validation 668 checks to handle_dll_attribute (). */ 669 bool (* valid_dllimport_attribute_p) (tree decl); 670 671 /* Functions relating to calls - argument passing, returns, etc. */ 672 struct calls { 673 bool (*promote_function_args) (tree fntype); 674 bool (*promote_function_return) (tree fntype); 675 bool (*promote_prototypes) (tree fntype); 676 rtx (*struct_value_rtx) (tree fndecl, int incoming); 677 bool (*return_in_memory) (tree type, tree fndecl); 678 bool (*return_in_msb) (tree type); 679 680 /* Return true if a parameter must be passed by reference. TYPE may 681 be null if this is a libcall. CA may be null if this query is 682 from __builtin_va_arg. */ 683 bool (*pass_by_reference) (CUMULATIVE_ARGS *ca, enum machine_mode mode, 684 tree type, bool named_arg); 685 686 rtx (*expand_builtin_saveregs) (void); 687 /* Returns pretend_argument_size. */ 688 void (*setup_incoming_varargs) (CUMULATIVE_ARGS *ca, enum machine_mode mode, 689 tree type, int *pretend_arg_size, 690 int second_time); 691 bool (*strict_argument_naming) (CUMULATIVE_ARGS *ca); 692 /* Returns true if we should use 693 targetm.calls.setup_incoming_varargs() and/or 694 targetm.calls.strict_argument_naming(). */ 695 bool (*pretend_outgoing_varargs_named) (CUMULATIVE_ARGS *ca); 696 697 /* Given a complex type T, return true if a parameter of type T 698 should be passed as two scalars. */ 699 bool (* split_complex_arg) (tree type); 700 701 /* Return true if type T, mode MODE, may not be passed in registers, 702 but must be passed on the stack. */ 703 /* ??? This predicate should be applied strictly after pass-by-reference. 704 Need audit to verify that this is the case. */ 705 bool (* must_pass_in_stack) (enum machine_mode mode, tree t); 706 707 /* Return true if type TYPE, mode MODE, which is passed by reference, 708 should have the object copy generated by the callee rather than 709 the caller. It is never called for TYPE requiring constructors. */ 710 bool (* callee_copies) (CUMULATIVE_ARGS *ca, enum machine_mode mode, 711 tree type, bool named); 712 713 /* Return zero for arguments passed entirely on the stack or entirely 714 in registers. If passed in both, return the number of bytes passed 715 in registers; the balance is therefore passed on the stack. */ 716 int (* arg_partial_bytes) (CUMULATIVE_ARGS *ca, enum machine_mode mode, 717 tree type, bool named); 718 719 /* Return the diagnostic message string if function without a prototype 720 is not allowed for this 'val' argument; NULL otherwise. */ 721 const char *(*invalid_arg_for_unprototyped_fn) (tree typelist, 722 tree funcdecl, tree val); 723 724 /* Return an rtx for the return value location of the function 725 specified by FN_DECL_OR_TYPE with a return type of RET_TYPE. */ 726 rtx (*function_value) (tree ret_type, tree fn_decl_or_type, 727 bool outgoing); 728 729 /* Return an rtx for the argument pointer incoming to the 730 current function. */ 731 rtx (*internal_arg_pointer) (void); 732 } calls; 733 734 /* Return the diagnostic message string if conversion from FROMTYPE 735 to TOTYPE is not allowed, NULL otherwise. */ 736 const char *(*invalid_conversion) (tree fromtype, tree totype); 737 738 /* Return the diagnostic message string if the unary operation OP is 739 not permitted on TYPE, NULL otherwise. */ 740 const char *(*invalid_unary_op) (int op, tree type); 741 742 /* Return the diagnostic message string if the binary operation OP 743 is not permitted on TYPE1 and TYPE2, NULL otherwise. */ 744 const char *(*invalid_binary_op) (int op, tree type1, tree type2); 745 746 /* Return the class for a secondary reload, and fill in extra information. */ 747 enum reg_class (*secondary_reload) (bool, rtx, enum reg_class, 748 enum machine_mode, 749 struct secondary_reload_info *); 750 751 /* Functions specific to the C++ frontend. */ 752 struct cxx { 753 /* Return the integer type used for guard variables. */ 754 tree (*guard_type) (void); 755 /* Return true if only the low bit of the guard should be tested. */ 756 bool (*guard_mask_bit) (void); 757 /* Returns the size of the array cookie for an array of type. */ 758 tree (*get_cookie_size) (tree); 759 /* Returns true if the element size should be stored in the 760 array cookie. */ 761 bool (*cookie_has_size) (void); 762 /* Allows backends to perform additional processing when 763 deciding if a class should be exported or imported. */ 764 int (*import_export_class) (tree, int); 765 /* Returns true if constructors and destructors return "this". */ 766 bool (*cdtor_returns_this) (void); 767 /* Returns true if the key method for a class can be an inline 768 function, so long as it is not declared inline in the class 769 itself. Returning true is the behavior required by the Itanium 770 C++ ABI. */ 771 bool (*key_method_may_be_inline) (void); 772 /* DECL is a virtual table, virtual table table, typeinfo object, 773 or other similar implicit class data object that will be 774 emitted with external linkage in this translation unit. No ELF 775 visibility has been explicitly specified. If the target needs 776 to specify a visibility other than that of the containing class, 777 use this hook to set DECL_VISIBILITY and 778 DECL_VISIBILITY_SPECIFIED. */ 779 void (*determine_class_data_visibility) (tree decl); 780 /* Returns true (the default) if virtual tables and other 781 similar implicit class data objects are always COMDAT if they 782 have external linkage. If this hook returns false, then 783 class data for classes whose virtual table will be emitted in 784 only one translation unit will not be COMDAT. */ 785 bool (*class_data_always_comdat) (void); 786 /* Returns true (the default) if the RTTI for the basic types, 787 which is always defined in the C++ runtime, should be COMDAT; 788 false if it should not be COMDAT. */ 789 bool (*library_rtti_comdat) (void); 790 /* Returns true if __aeabi_atexit should be used to register static 791 destructors. */ 792 bool (*use_aeabi_atexit) (void); 793 /* TYPE is a C++ class (i.e., RECORD_TYPE or UNION_TYPE) that 794 has just been defined. Use this hook to make adjustments to the 795 class (eg, tweak visibility or perform any other required 796 target modifications). */ 797 void (*adjust_class_at_definition) (tree type); 798 } cxx; 799 800 /* For targets that need to mark extra registers as live on entry to 801 the function, they should define this target hook and set their 802 bits in the bitmap passed in. */ 803 void (*live_on_entry) (bitmap); 804 805 /* True if unwinding tables should be generated by default. */ 806 bool unwind_tables_default; 807 808 /* Leave the boolean fields at the end. */ 809 810 /* True if arbitrary sections are supported. */ 811 bool have_named_sections; 812 813 /* True if we can create zeroed data by switching to a BSS section 814 and then using ASM_OUTPUT_SKIP to allocate the space. */ 815 bool have_switchable_bss_sections; 816 817 /* True if "native" constructors and destructors are supported, 818 false if we're using collect2 for the job. */ 819 bool have_ctors_dtors; 820 821 /* True if thread-local storage is supported. */ 822 bool have_tls; 823 824 /* True if a small readonly data section is supported. */ 825 bool have_srodata_section; 826 827 /* True if EH frame info sections should be zero-terminated. */ 828 bool terminate_dw2_eh_frame_info; 829 830 /* True if #NO_APP should be emitted at the beginning of 831 assembly output. */ 832 bool file_start_app_off; 833 834 /* True if output_file_directive should be called for main_input_filename 835 at the beginning of assembly output. */ 836 bool file_start_file_directive; 837 838 /* True if #pragma redefine_extname is to be supported. */ 839 bool handle_pragma_redefine_extname; 840 841 /* True if #pragma extern_prefix is to be supported. */ 842 bool handle_pragma_extern_prefix; 843 844 /* True if the target is allowed to reorder memory accesses unless 845 synchronization is explicitly requested. */ 846 bool relaxed_ordering; 847 848 /* Returns true if we should generate exception tables for use with the 849 ARM EABI. The effects the encoding of function exception specifications. 850 */ 851 bool arm_eabi_unwinder; 852 853 /* Leave the boolean fields at the end. */ 854 }; 855 856 extern struct gcc_target targetm; 857 858 #endif /* GCC_TARGET_H */ 859