1/* Default target hook functions. 2 Copyright (C) 2003, 2004, 2005, 2007 Free Software Foundation, Inc. 3 4This file is part of GCC. 5 6GCC is free software; you can redistribute it and/or modify it under 7the terms of the GNU General Public License as published by the Free 8Software Foundation; either version 2, or (at your option) any later 9version. 10 11GCC is distributed in the hope that it will be useful, but WITHOUT ANY 12WARRANTY; without even the implied warranty of MERCHANTABILITY or 13FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14for more details. 15 16You should have received a copy of the GNU General Public License 17along with GCC; see the file COPYING. If not, write to the Free 18Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 1902110-1301, USA. */ 20 21/* The migration of target macros to target hooks works as follows: 22 23 1. Create a target hook that uses the existing target macros to 24 implement the same functionality. 25 26 2. Convert all the MI files to use the hook instead of the macro. 27 28 3. Repeat for a majority of the remaining target macros. This will 29 take some time. 30 31 4. Tell target maintainers to start migrating. 32 33 5. Eventually convert the backends to override the hook instead of 34 defining the macros. This will take some time too. 35 36 6. TBD when, poison the macros. Unmigrated targets will break at 37 this point. 38 39 Note that we expect steps 1-3 to be done by the people that 40 understand what the MI does with each macro, and step 5 to be done 41 by the target maintainers for their respective targets. 42 43 Note that steps 1 and 2 don't have to be done together, but no 44 target can override the new hook until step 2 is complete for it. 45 46 Once the macros are poisoned, we will revert to the old migration 47 rules - migrate the macro, callers, and targets all at once. This 48 comment can thus be removed at that point. */ 49 50#include "config.h" 51#include "system.h" 52#include "coretypes.h" 53#include "tm.h" 54#include "machmode.h" 55#include "rtl.h" 56#include "tree.h" 57#include "expr.h" 58#include "output.h" 59#include "toplev.h" 60#include "function.h" 61#include "target.h" 62#include "tm_p.h" 63#include "target-def.h" 64#include "ggc.h" 65#include "hard-reg-set.h" 66#include "reload.h" 67#include "optabs.h" 68#include "recog.h" 69 70 71void 72default_external_libcall (rtx fun ATTRIBUTE_UNUSED) 73{ 74#ifdef ASM_OUTPUT_EXTERNAL_LIBCALL 75 ASM_OUTPUT_EXTERNAL_LIBCALL(asm_out_file, fun); 76#endif 77} 78 79enum machine_mode 80default_cc_modes_compatible (enum machine_mode m1, enum machine_mode m2) 81{ 82 if (m1 == m2) 83 return m1; 84 return VOIDmode; 85} 86 87bool 88default_return_in_memory (tree type, 89 tree fntype ATTRIBUTE_UNUSED) 90{ 91#ifndef RETURN_IN_MEMORY 92 return (TYPE_MODE (type) == BLKmode); 93#else 94 return RETURN_IN_MEMORY (type); 95#endif 96} 97 98/* APPLE LOCAL begin radar 4781080 */ 99bool 100default_objc_fpreturn_msgcall (tree type, bool no_long_double) 101{ 102#ifndef OBJC_FPRETURN_MSGCALL 103 return type == NULL_TREE && no_long_double; 104#else 105 return OBJC_FPRETURN_MSGCALL (type, no_long_double); 106#endif 107} 108/* APPLE LOCAL end radar 4781080 */ 109 110rtx 111default_expand_builtin_saveregs (void) 112{ 113 error ("__builtin_saveregs not supported by this target"); 114 return const0_rtx; 115} 116 117void 118default_setup_incoming_varargs (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED, 119 enum machine_mode mode ATTRIBUTE_UNUSED, 120 tree type ATTRIBUTE_UNUSED, 121 int *pretend_arg_size ATTRIBUTE_UNUSED, 122 int second_time ATTRIBUTE_UNUSED) 123{ 124} 125 126/* The default implementation of TARGET_BUILTIN_SETJMP_FRAME_VALUE. */ 127 128rtx 129default_builtin_setjmp_frame_value (void) 130{ 131 return virtual_stack_vars_rtx; 132} 133 134/* Generic hook that takes a CUMULATIVE_ARGS pointer and returns false. */ 135 136bool 137hook_bool_CUMULATIVE_ARGS_false (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED) 138{ 139 return false; 140} 141 142bool 143default_pretend_outgoing_varargs_named (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED) 144{ 145 return (targetm.calls.setup_incoming_varargs 146 != default_setup_incoming_varargs); 147} 148 149enum machine_mode 150default_eh_return_filter_mode (void) 151{ 152 return word_mode; 153} 154 155/* The default implementation of TARGET_SHIFT_TRUNCATION_MASK. */ 156 157unsigned HOST_WIDE_INT 158default_shift_truncation_mask (enum machine_mode mode) 159{ 160 return SHIFT_COUNT_TRUNCATED ? GET_MODE_BITSIZE (mode) - 1 : 0; 161} 162 163/* The default implementation of TARGET_MIN_DIVISIONS_FOR_RECIP_MUL. */ 164 165unsigned int 166default_min_divisions_for_recip_mul (enum machine_mode mode ATTRIBUTE_UNUSED) 167{ 168 return have_insn_for (DIV, mode) ? 3 : 2; 169} 170 171/* The default implementation of TARGET_MODE_REP_EXTENDED. */ 172 173int 174default_mode_rep_extended (enum machine_mode mode ATTRIBUTE_UNUSED, 175 enum machine_mode mode_rep ATTRIBUTE_UNUSED) 176{ 177 return UNKNOWN; 178} 179 180/* Generic hook that takes a CUMULATIVE_ARGS pointer and returns true. */ 181 182bool 183hook_bool_CUMULATIVE_ARGS_true (CUMULATIVE_ARGS * a ATTRIBUTE_UNUSED) 184{ 185 return true; 186} 187 188 189/* The generic C++ ABI specifies this is a 64-bit value. */ 190tree 191default_cxx_guard_type (void) 192{ 193 return long_long_integer_type_node; 194} 195 196 197/* Returns the size of the cookie to use when allocating an array 198 whose elements have the indicated TYPE. Assumes that it is already 199 known that a cookie is needed. */ 200 201tree 202default_cxx_get_cookie_size (tree type) 203{ 204 tree cookie_size; 205 206 /* We need to allocate an additional max (sizeof (size_t), alignof 207 (true_type)) bytes. */ 208 tree sizetype_size; 209 tree type_align; 210 211 sizetype_size = size_in_bytes (sizetype); 212 type_align = size_int (TYPE_ALIGN_UNIT (type)); 213 if (INT_CST_LT_UNSIGNED (type_align, sizetype_size)) 214 cookie_size = sizetype_size; 215 else 216 cookie_size = type_align; 217 218 return cookie_size; 219} 220 221/* Return true if a parameter must be passed by reference. This version 222 of the TARGET_PASS_BY_REFERENCE hook uses just MUST_PASS_IN_STACK. */ 223 224bool 225hook_pass_by_reference_must_pass_in_stack (CUMULATIVE_ARGS *c ATTRIBUTE_UNUSED, 226 enum machine_mode mode ATTRIBUTE_UNUSED, tree type ATTRIBUTE_UNUSED, 227 bool named_arg ATTRIBUTE_UNUSED) 228{ 229 return targetm.calls.must_pass_in_stack (mode, type); 230} 231 232/* Return true if a parameter follows callee copies conventions. This 233 version of the hook is true for all named arguments. */ 234 235bool 236hook_callee_copies_named (CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED, 237 enum machine_mode mode ATTRIBUTE_UNUSED, 238 tree type ATTRIBUTE_UNUSED, bool named) 239{ 240 return named; 241} 242 243/* Emit any directives required to unwind this instruction. */ 244 245void 246default_unwind_emit (FILE * stream ATTRIBUTE_UNUSED, 247 rtx insn ATTRIBUTE_UNUSED) 248{ 249 /* Should never happen. */ 250 gcc_unreachable (); 251} 252 253/* True if MODE is valid for the target. By "valid", we mean able to 254 be manipulated in non-trivial ways. In particular, this means all 255 the arithmetic is supported. 256 257 By default we guess this means that any C type is supported. If 258 we can't map the mode back to a type that would be available in C, 259 then reject it. Special case, here, is the double-word arithmetic 260 supported by optabs.c. */ 261 262bool 263default_scalar_mode_supported_p (enum machine_mode mode) 264{ 265 int precision = GET_MODE_PRECISION (mode); 266 267 switch (GET_MODE_CLASS (mode)) 268 { 269 case MODE_PARTIAL_INT: 270 case MODE_INT: 271 if (precision == CHAR_TYPE_SIZE) 272 return true; 273 if (precision == SHORT_TYPE_SIZE) 274 return true; 275 if (precision == INT_TYPE_SIZE) 276 return true; 277 if (precision == LONG_TYPE_SIZE) 278 return true; 279 if (precision == LONG_LONG_TYPE_SIZE) 280 return true; 281 if (precision == 2 * BITS_PER_WORD) 282 return true; 283 return false; 284 285 case MODE_FLOAT: 286 if (precision == FLOAT_TYPE_SIZE) 287 return true; 288 if (precision == DOUBLE_TYPE_SIZE) 289 return true; 290 if (precision == LONG_DOUBLE_TYPE_SIZE) 291 return true; 292 return false; 293 294 case MODE_DECIMAL_FLOAT: 295 return false; 296 297 default: 298 gcc_unreachable (); 299 } 300} 301 302/* True if the target supports decimal floating point. */ 303 304bool 305default_decimal_float_supported_p (void) 306{ 307 return ENABLE_DECIMAL_FLOAT; 308} 309 310/* NULL if INSN insn is valid within a low-overhead loop, otherwise returns 311 an error message. 312 313 This function checks whether a given INSN is valid within a low-overhead 314 loop. If INSN is invalid it returns the reason for that, otherwise it 315 returns NULL. A called function may clobber any special registers required 316 for low-overhead looping. Additionally, some targets (eg, PPC) use the count 317 register for branch on table instructions. We reject the doloop pattern in 318 these cases. */ 319 320const char * 321default_invalid_within_doloop (rtx insn) 322{ 323 if (CALL_P (insn)) 324 return "Function call in loop."; 325 326 if (JUMP_P (insn) 327 && (GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC 328 || GET_CODE (PATTERN (insn)) == ADDR_VEC)) 329 return "Computed branch in the loop."; 330 331 return NULL; 332} 333 334bool 335hook_bool_CUMULATIVE_ARGS_mode_tree_bool_false ( 336 CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED, 337 enum machine_mode mode ATTRIBUTE_UNUSED, 338 tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED) 339{ 340 return false; 341} 342 343bool 344hook_bool_CUMULATIVE_ARGS_mode_tree_bool_true ( 345 CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED, 346 enum machine_mode mode ATTRIBUTE_UNUSED, 347 tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED) 348{ 349 return true; 350} 351 352int 353hook_int_CUMULATIVE_ARGS_mode_tree_bool_0 ( 354 CUMULATIVE_ARGS *ca ATTRIBUTE_UNUSED, 355 enum machine_mode mode ATTRIBUTE_UNUSED, 356 tree type ATTRIBUTE_UNUSED, bool named ATTRIBUTE_UNUSED) 357{ 358 return 0; 359} 360 361void 362hook_void_bitmap (bitmap regs ATTRIBUTE_UNUSED) 363{ 364} 365 366const char * 367hook_invalid_arg_for_unprototyped_fn ( 368 tree typelist ATTRIBUTE_UNUSED, 369 tree funcdecl ATTRIBUTE_UNUSED, 370 tree val ATTRIBUTE_UNUSED) 371{ 372 return NULL; 373} 374 375/* Initialize the stack protection decls. */ 376 377/* Stack protection related decls living in libgcc. */ 378static GTY(()) tree stack_chk_guard_decl; 379 380tree 381default_stack_protect_guard (void) 382{ 383 tree t = stack_chk_guard_decl; 384 385 if (t == NULL) 386 { 387 t = build_decl (VAR_DECL, get_identifier ("__stack_chk_guard"), 388 ptr_type_node); 389 TREE_STATIC (t) = 1; 390 TREE_PUBLIC (t) = 1; 391 DECL_EXTERNAL (t) = 1; 392 TREE_USED (t) = 1; 393 TREE_THIS_VOLATILE (t) = 1; 394 DECL_ARTIFICIAL (t) = 1; 395 DECL_IGNORED_P (t) = 1; 396 397 stack_chk_guard_decl = t; 398 } 399 400 return t; 401} 402 403static GTY(()) tree stack_chk_fail_decl; 404 405tree 406default_external_stack_protect_fail (void) 407{ 408 tree t = stack_chk_fail_decl; 409 410 if (t == NULL_TREE) 411 { 412 t = build_function_type_list (void_type_node, NULL_TREE); 413 t = build_decl (FUNCTION_DECL, get_identifier ("__stack_chk_fail"), t); 414 TREE_STATIC (t) = 1; 415 TREE_PUBLIC (t) = 1; 416 DECL_EXTERNAL (t) = 1; 417 TREE_USED (t) = 1; 418 TREE_THIS_VOLATILE (t) = 1; 419 TREE_NOTHROW (t) = 1; 420 DECL_ARTIFICIAL (t) = 1; 421 DECL_IGNORED_P (t) = 1; 422 DECL_VISIBILITY (t) = VISIBILITY_DEFAULT; 423 DECL_VISIBILITY_SPECIFIED (t) = 1; 424 425 stack_chk_fail_decl = t; 426 } 427 428 return build_function_call_expr (t, NULL_TREE); 429} 430 431tree 432default_hidden_stack_protect_fail (void) 433{ 434#ifndef HAVE_GAS_HIDDEN 435 return default_external_stack_protect_fail (); 436#else 437 tree t = stack_chk_fail_decl; 438 439 if (!flag_pic) 440 return default_external_stack_protect_fail (); 441 442 if (t == NULL_TREE) 443 { 444 t = build_function_type_list (void_type_node, NULL_TREE); 445 t = build_decl (FUNCTION_DECL, 446 get_identifier ("__stack_chk_fail_local"), t); 447 TREE_STATIC (t) = 1; 448 TREE_PUBLIC (t) = 1; 449 DECL_EXTERNAL (t) = 1; 450 TREE_USED (t) = 1; 451 TREE_THIS_VOLATILE (t) = 1; 452 TREE_NOTHROW (t) = 1; 453 DECL_ARTIFICIAL (t) = 1; 454 DECL_IGNORED_P (t) = 1; 455 DECL_VISIBILITY_SPECIFIED (t) = 1; 456 DECL_VISIBILITY (t) = VISIBILITY_HIDDEN; 457 458 stack_chk_fail_decl = t; 459 } 460 461 return build_function_call_expr (t, NULL_TREE); 462#endif 463} 464 465bool 466hook_bool_rtx_commutative_p (rtx x, int outer_code ATTRIBUTE_UNUSED) 467{ 468 return COMMUTATIVE_P (x); 469} 470 471rtx 472default_function_value (tree ret_type ATTRIBUTE_UNUSED, 473 tree fn_decl_or_type, 474 bool outgoing ATTRIBUTE_UNUSED) 475{ 476 /* The old interface doesn't handle receiving the function type. */ 477 if (fn_decl_or_type 478 && !DECL_P (fn_decl_or_type)) 479 fn_decl_or_type = NULL; 480 481#ifdef FUNCTION_OUTGOING_VALUE 482 if (outgoing) 483 return FUNCTION_OUTGOING_VALUE (ret_type, fn_decl_or_type); 484#endif 485 486#ifdef FUNCTION_VALUE 487 return FUNCTION_VALUE (ret_type, fn_decl_or_type); 488#else 489 return NULL_RTX; 490#endif 491} 492 493rtx 494default_internal_arg_pointer (void) 495{ 496 /* If the reg that the virtual arg pointer will be translated into is 497 not a fixed reg or is the stack pointer, make a copy of the virtual 498 arg pointer, and address parms via the copy. The frame pointer is 499 considered fixed even though it is not marked as such. */ 500 if ((ARG_POINTER_REGNUM == STACK_POINTER_REGNUM 501 || ! (fixed_regs[ARG_POINTER_REGNUM] 502 || ARG_POINTER_REGNUM == FRAME_POINTER_REGNUM))) 503 return copy_to_reg (virtual_incoming_args_rtx); 504 else 505 return virtual_incoming_args_rtx; 506} 507 508enum reg_class 509default_secondary_reload (bool in_p ATTRIBUTE_UNUSED, rtx x ATTRIBUTE_UNUSED, 510 enum reg_class reload_class ATTRIBUTE_UNUSED, 511 enum machine_mode reload_mode ATTRIBUTE_UNUSED, 512 secondary_reload_info *sri) 513{ 514 enum reg_class class = NO_REGS; 515 516 if (sri->prev_sri && sri->prev_sri->t_icode != CODE_FOR_nothing) 517 { 518 sri->icode = sri->prev_sri->t_icode; 519 return NO_REGS; 520 } 521#ifdef SECONDARY_INPUT_RELOAD_CLASS 522 if (in_p) 523 class = SECONDARY_INPUT_RELOAD_CLASS (reload_class, reload_mode, x); 524#endif 525#ifdef SECONDARY_OUTPUT_RELOAD_CLASS 526 if (! in_p) 527 class = SECONDARY_OUTPUT_RELOAD_CLASS (reload_class, reload_mode, x); 528#endif 529 if (class != NO_REGS) 530 { 531 enum insn_code icode = (in_p ? reload_in_optab[(int) reload_mode] 532 : reload_out_optab[(int) reload_mode]); 533 534 if (icode != CODE_FOR_nothing 535 && insn_data[(int) icode].operand[in_p].predicate 536 && ! insn_data[(int) icode].operand[in_p].predicate (x, reload_mode)) 537 icode = CODE_FOR_nothing; 538 else if (icode != CODE_FOR_nothing) 539 { 540 const char *insn_constraint, *scratch_constraint; 541 char insn_letter, scratch_letter; 542 enum reg_class insn_class, scratch_class; 543 544 gcc_assert (insn_data[(int) icode].n_operands == 3); 545 insn_constraint = insn_data[(int) icode].operand[!in_p].constraint; 546 if (!*insn_constraint) 547 insn_class = ALL_REGS; 548 else 549 { 550 if (in_p) 551 { 552 gcc_assert (*insn_constraint == '='); 553 insn_constraint++; 554 } 555 insn_letter = *insn_constraint; 556 insn_class 557 = (insn_letter == 'r' ? GENERAL_REGS 558 : REG_CLASS_FROM_CONSTRAINT ((unsigned char) insn_letter, 559 insn_constraint)); 560 gcc_assert (insn_class != NO_REGS); 561 } 562 563 scratch_constraint = insn_data[(int) icode].operand[2].constraint; 564 /* The scratch register's constraint must start with "=&", 565 except for an input reload, where only "=" is necessary, 566 and where it might be beneficial to re-use registers from 567 the input. */ 568 gcc_assert (scratch_constraint[0] == '=' 569 && (in_p || scratch_constraint[1] == '&')); 570 scratch_constraint++; 571 if (*scratch_constraint == '&') 572 scratch_constraint++; 573 scratch_letter = *scratch_constraint; 574 scratch_class 575 = (scratch_letter == 'r' ? GENERAL_REGS 576 : REG_CLASS_FROM_CONSTRAINT ((unsigned char) scratch_letter, 577 scratch_constraint)); 578 579 if (reg_class_subset_p (reload_class, insn_class)) 580 { 581 gcc_assert (scratch_class == class); 582 class = NO_REGS; 583 } 584 else 585 class = insn_class; 586 587 } 588 if (class == NO_REGS) 589 sri->icode = icode; 590 else 591 sri->t_icode = icode; 592 } 593 return class; 594} 595 596 597/* If STRICT_ALIGNMENT is true we use the container type for accessing 598 volatile bitfields. This is generally the preferred behavior for memory 599 mapped peripherals on RISC architectures. 600 If STRICT_ALIGNMENT is false we use the narrowest type possible. This 601 is typically used to avoid spurious page faults and extra memory accesses 602 due to unaligned accesses on CISC architectures. */ 603 604bool 605default_narrow_bitfield (void) 606{ 607 return !STRICT_ALIGNMENT; 608} 609 610/* By default, if flag_pic is true, then neither local nor global relocs 611 should be placed in readonly memory. */ 612 613int 614default_reloc_rw_mask (void) 615{ 616 return flag_pic ? 3 : 0; 617} 618 619bool 620default_builtin_vector_alignment_reachable (tree type, bool is_packed) 621{ 622 if (is_packed) 623 return false; 624 625 /* Assuming that types whose size is > pointer-size are not guaranteed to be 626 naturally aligned. */ 627 if (tree_int_cst_compare (TYPE_SIZE (type), bitsize_int (POINTER_SIZE)) > 0) 628 return false; 629 630 /* Assuming that types whose size is <= pointer-size 631 are naturally aligned. */ 632 return true; 633} 634 635#include "gt-targhooks.h" 636