explow.c revision 18334
1/* Subroutines for manipulating rtx's in semantically interesting ways. 2 Copyright (C) 1987, 1991, 1994, 1995 Free Software Foundation, Inc. 3 4This file is part of GNU CC. 5 6GNU CC is free software; you can redistribute it and/or modify 7it under the terms of the GNU General Public License as published by 8the Free Software Foundation; either version 2, or (at your option) 9any later version. 10 11GNU CC is distributed in the hope that it will be useful, 12but WITHOUT ANY WARRANTY; without even the implied warranty of 13MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14GNU General Public License for more details. 15 16You should have received a copy of the GNU General Public License 17along with GNU CC; see the file COPYING. If not, write to 18the Free Software Foundation, 59 Temple Place - Suite 330, 19Boston, MA 02111-1307, USA. */ 20 21 22#include "config.h" 23#include "rtl.h" 24#include "tree.h" 25#include "flags.h" 26#include "expr.h" 27#include "hard-reg-set.h" 28#include "insn-config.h" 29#include "recog.h" 30#include "insn-flags.h" 31#include "insn-codes.h" 32 33static rtx break_out_memory_refs PROTO((rtx)); 34 35/* Return an rtx for the sum of X and the integer C. 36 37 This function should be used via the `plus_constant' macro. */ 38 39rtx 40plus_constant_wide (x, c) 41 register rtx x; 42 register HOST_WIDE_INT c; 43{ 44 register RTX_CODE code; 45 register enum machine_mode mode; 46 register rtx tem; 47 int all_constant = 0; 48 49 if (c == 0) 50 return x; 51 52 restart: 53 54 code = GET_CODE (x); 55 mode = GET_MODE (x); 56 switch (code) 57 { 58 case CONST_INT: 59 return GEN_INT (INTVAL (x) + c); 60 61 case CONST_DOUBLE: 62 { 63 HOST_WIDE_INT l1 = CONST_DOUBLE_LOW (x); 64 HOST_WIDE_INT h1 = CONST_DOUBLE_HIGH (x); 65 HOST_WIDE_INT l2 = c; 66 HOST_WIDE_INT h2 = c < 0 ? ~0 : 0; 67 HOST_WIDE_INT lv, hv; 68 69 add_double (l1, h1, l2, h2, &lv, &hv); 70 71 return immed_double_const (lv, hv, VOIDmode); 72 } 73 74 case MEM: 75 /* If this is a reference to the constant pool, try replacing it with 76 a reference to a new constant. If the resulting address isn't 77 valid, don't return it because we have no way to validize it. */ 78 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF 79 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0))) 80 { 81 tem 82 = force_const_mem (GET_MODE (x), 83 plus_constant (get_pool_constant (XEXP (x, 0)), 84 c)); 85 if (memory_address_p (GET_MODE (tem), XEXP (tem, 0))) 86 return tem; 87 } 88 break; 89 90 case CONST: 91 /* If adding to something entirely constant, set a flag 92 so that we can add a CONST around the result. */ 93 x = XEXP (x, 0); 94 all_constant = 1; 95 goto restart; 96 97 case SYMBOL_REF: 98 case LABEL_REF: 99 all_constant = 1; 100 break; 101 102 case PLUS: 103 /* The interesting case is adding the integer to a sum. 104 Look for constant term in the sum and combine 105 with C. For an integer constant term, we make a combined 106 integer. For a constant term that is not an explicit integer, 107 we cannot really combine, but group them together anyway. 108 109 Use a recursive call in case the remaining operand is something 110 that we handle specially, such as a SYMBOL_REF. */ 111 112 if (GET_CODE (XEXP (x, 1)) == CONST_INT) 113 return plus_constant (XEXP (x, 0), c + INTVAL (XEXP (x, 1))); 114 else if (CONSTANT_P (XEXP (x, 0))) 115 return gen_rtx (PLUS, mode, 116 plus_constant (XEXP (x, 0), c), 117 XEXP (x, 1)); 118 else if (CONSTANT_P (XEXP (x, 1))) 119 return gen_rtx (PLUS, mode, 120 XEXP (x, 0), 121 plus_constant (XEXP (x, 1), c)); 122 } 123 124 if (c != 0) 125 x = gen_rtx (PLUS, mode, x, GEN_INT (c)); 126 127 if (GET_CODE (x) == SYMBOL_REF || GET_CODE (x) == LABEL_REF) 128 return x; 129 else if (all_constant) 130 return gen_rtx (CONST, mode, x); 131 else 132 return x; 133} 134 135/* This is the same as `plus_constant', except that it handles LO_SUM. 136 137 This function should be used via the `plus_constant_for_output' macro. */ 138 139rtx 140plus_constant_for_output_wide (x, c) 141 register rtx x; 142 register HOST_WIDE_INT c; 143{ 144 register RTX_CODE code = GET_CODE (x); 145 register enum machine_mode mode = GET_MODE (x); 146 int all_constant = 0; 147 148 if (GET_CODE (x) == LO_SUM) 149 return gen_rtx (LO_SUM, mode, XEXP (x, 0), 150 plus_constant_for_output (XEXP (x, 1), c)); 151 152 else 153 return plus_constant (x, c); 154} 155 156/* If X is a sum, return a new sum like X but lacking any constant terms. 157 Add all the removed constant terms into *CONSTPTR. 158 X itself is not altered. The result != X if and only if 159 it is not isomorphic to X. */ 160 161rtx 162eliminate_constant_term (x, constptr) 163 rtx x; 164 rtx *constptr; 165{ 166 register rtx x0, x1; 167 rtx tem; 168 169 if (GET_CODE (x) != PLUS) 170 return x; 171 172 /* First handle constants appearing at this level explicitly. */ 173 if (GET_CODE (XEXP (x, 1)) == CONST_INT 174 && 0 != (tem = simplify_binary_operation (PLUS, GET_MODE (x), *constptr, 175 XEXP (x, 1))) 176 && GET_CODE (tem) == CONST_INT) 177 { 178 *constptr = tem; 179 return eliminate_constant_term (XEXP (x, 0), constptr); 180 } 181 182 tem = const0_rtx; 183 x0 = eliminate_constant_term (XEXP (x, 0), &tem); 184 x1 = eliminate_constant_term (XEXP (x, 1), &tem); 185 if ((x1 != XEXP (x, 1) || x0 != XEXP (x, 0)) 186 && 0 != (tem = simplify_binary_operation (PLUS, GET_MODE (x), 187 *constptr, tem)) 188 && GET_CODE (tem) == CONST_INT) 189 { 190 *constptr = tem; 191 return gen_rtx (PLUS, GET_MODE (x), x0, x1); 192 } 193 194 return x; 195} 196 197/* Returns the insn that next references REG after INSN, or 0 198 if REG is clobbered before next referenced or we cannot find 199 an insn that references REG in a straight-line piece of code. */ 200 201rtx 202find_next_ref (reg, insn) 203 rtx reg; 204 rtx insn; 205{ 206 rtx next; 207 208 for (insn = NEXT_INSN (insn); insn; insn = next) 209 { 210 next = NEXT_INSN (insn); 211 if (GET_CODE (insn) == NOTE) 212 continue; 213 if (GET_CODE (insn) == CODE_LABEL 214 || GET_CODE (insn) == BARRIER) 215 return 0; 216 if (GET_CODE (insn) == INSN 217 || GET_CODE (insn) == JUMP_INSN 218 || GET_CODE (insn) == CALL_INSN) 219 { 220 if (reg_set_p (reg, insn)) 221 return 0; 222 if (reg_mentioned_p (reg, PATTERN (insn))) 223 return insn; 224 if (GET_CODE (insn) == JUMP_INSN) 225 { 226 if (simplejump_p (insn)) 227 next = JUMP_LABEL (insn); 228 else 229 return 0; 230 } 231 if (GET_CODE (insn) == CALL_INSN 232 && REGNO (reg) < FIRST_PSEUDO_REGISTER 233 && call_used_regs[REGNO (reg)]) 234 return 0; 235 } 236 else 237 abort (); 238 } 239 return 0; 240} 241 242/* Return an rtx for the size in bytes of the value of EXP. */ 243 244rtx 245expr_size (exp) 246 tree exp; 247{ 248 tree size = size_in_bytes (TREE_TYPE (exp)); 249 250 if (TREE_CODE (size) != INTEGER_CST 251 && contains_placeholder_p (size)) 252 size = build (WITH_RECORD_EXPR, sizetype, size, exp); 253 254 return expand_expr (size, NULL_RTX, TYPE_MODE (sizetype), 0); 255} 256 257/* Return a copy of X in which all memory references 258 and all constants that involve symbol refs 259 have been replaced with new temporary registers. 260 Also emit code to load the memory locations and constants 261 into those registers. 262 263 If X contains no such constants or memory references, 264 X itself (not a copy) is returned. 265 266 If a constant is found in the address that is not a legitimate constant 267 in an insn, it is left alone in the hope that it might be valid in the 268 address. 269 270 X may contain no arithmetic except addition, subtraction and multiplication. 271 Values returned by expand_expr with 1 for sum_ok fit this constraint. */ 272 273static rtx 274break_out_memory_refs (x) 275 register rtx x; 276{ 277 if (GET_CODE (x) == MEM 278 || (CONSTANT_P (x) && CONSTANT_ADDRESS_P (x) 279 && GET_MODE (x) != VOIDmode)) 280 x = force_reg (GET_MODE (x), x); 281 else if (GET_CODE (x) == PLUS || GET_CODE (x) == MINUS 282 || GET_CODE (x) == MULT) 283 { 284 register rtx op0 = break_out_memory_refs (XEXP (x, 0)); 285 register rtx op1 = break_out_memory_refs (XEXP (x, 1)); 286 287 if (op0 != XEXP (x, 0) || op1 != XEXP (x, 1)) 288 x = gen_rtx (GET_CODE (x), Pmode, op0, op1); 289 } 290 291 return x; 292} 293 294#ifdef POINTERS_EXTEND_UNSIGNED 295 296/* Given X, a memory address in ptr_mode, convert it to an address 297 in Pmode, or vice versa (TO_MODE says which way). We take advantage of 298 the fact that pointers are not allowed to overflow by commuting arithmetic 299 operations over conversions so that address arithmetic insns can be 300 used. */ 301 302rtx 303convert_memory_address (to_mode, x) 304 enum machine_mode to_mode; 305 rtx x; 306{ 307 rtx temp; 308 309 switch (GET_CODE (x)) 310 { 311 case CONST_INT: 312 case CONST_DOUBLE: 313 return x; 314 315 case LABEL_REF: 316 return gen_rtx (LABEL_REF, to_mode, XEXP (x, 0)); 317 318 case SYMBOL_REF: 319 temp = gen_rtx (SYMBOL_REF, to_mode, XSTR (x, 0)); 320 SYMBOL_REF_FLAG (temp) = SYMBOL_REF_FLAG (x); 321 return temp; 322 323 case PLUS: 324 case MULT: 325 return gen_rtx (GET_CODE (x), to_mode, 326 convert_memory_address (to_mode, XEXP (x, 0)), 327 convert_memory_address (to_mode, XEXP (x, 1))); 328 329 case CONST: 330 return gen_rtx (CONST, to_mode, 331 convert_memory_address (to_mode, XEXP (x, 0))); 332 333 default: 334 return convert_modes (to_mode, 335 to_mode == ptr_mode ? Pmode : ptr_mode, 336 x, POINTERS_EXTEND_UNSIGNED); 337 } 338} 339#endif 340 341/* Given a memory address or facsimile X, construct a new address, 342 currently equivalent, that is stable: future stores won't change it. 343 344 X must be composed of constants, register and memory references 345 combined with addition, subtraction and multiplication: 346 in other words, just what you can get from expand_expr if sum_ok is 1. 347 348 Works by making copies of all regs and memory locations used 349 by X and combining them the same way X does. 350 You could also stabilize the reference to this address 351 by copying the address to a register with copy_to_reg; 352 but then you wouldn't get indexed addressing in the reference. */ 353 354rtx 355copy_all_regs (x) 356 register rtx x; 357{ 358 if (GET_CODE (x) == REG) 359 { 360 if (REGNO (x) != FRAME_POINTER_REGNUM 361#if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM 362 && REGNO (x) != HARD_FRAME_POINTER_REGNUM 363#endif 364 ) 365 x = copy_to_reg (x); 366 } 367 else if (GET_CODE (x) == MEM) 368 x = copy_to_reg (x); 369 else if (GET_CODE (x) == PLUS || GET_CODE (x) == MINUS 370 || GET_CODE (x) == MULT) 371 { 372 register rtx op0 = copy_all_regs (XEXP (x, 0)); 373 register rtx op1 = copy_all_regs (XEXP (x, 1)); 374 if (op0 != XEXP (x, 0) || op1 != XEXP (x, 1)) 375 x = gen_rtx (GET_CODE (x), Pmode, op0, op1); 376 } 377 return x; 378} 379 380/* Return something equivalent to X but valid as a memory address 381 for something of mode MODE. When X is not itself valid, this 382 works by copying X or subexpressions of it into registers. */ 383 384rtx 385memory_address (mode, x) 386 enum machine_mode mode; 387 register rtx x; 388{ 389 register rtx oldx = x; 390 391#ifdef POINTERS_EXTEND_UNSIGNED 392 if (GET_MODE (x) == ptr_mode) 393 x = convert_memory_address (Pmode, x); 394#endif 395 396 /* By passing constant addresses thru registers 397 we get a chance to cse them. */ 398 if (! cse_not_expected && CONSTANT_P (x) && CONSTANT_ADDRESS_P (x)) 399 x = force_reg (Pmode, x); 400 401 /* Accept a QUEUED that refers to a REG 402 even though that isn't a valid address. 403 On attempting to put this in an insn we will call protect_from_queue 404 which will turn it into a REG, which is valid. */ 405 else if (GET_CODE (x) == QUEUED 406 && GET_CODE (QUEUED_VAR (x)) == REG) 407 ; 408 409 /* We get better cse by rejecting indirect addressing at this stage. 410 Let the combiner create indirect addresses where appropriate. 411 For now, generate the code so that the subexpressions useful to share 412 are visible. But not if cse won't be done! */ 413 else 414 { 415 if (! cse_not_expected && GET_CODE (x) != REG) 416 x = break_out_memory_refs (x); 417 418 /* At this point, any valid address is accepted. */ 419 GO_IF_LEGITIMATE_ADDRESS (mode, x, win); 420 421 /* If it was valid before but breaking out memory refs invalidated it, 422 use it the old way. */ 423 if (memory_address_p (mode, oldx)) 424 goto win2; 425 426 /* Perform machine-dependent transformations on X 427 in certain cases. This is not necessary since the code 428 below can handle all possible cases, but machine-dependent 429 transformations can make better code. */ 430 LEGITIMIZE_ADDRESS (x, oldx, mode, win); 431 432 /* PLUS and MULT can appear in special ways 433 as the result of attempts to make an address usable for indexing. 434 Usually they are dealt with by calling force_operand, below. 435 But a sum containing constant terms is special 436 if removing them makes the sum a valid address: 437 then we generate that address in a register 438 and index off of it. We do this because it often makes 439 shorter code, and because the addresses thus generated 440 in registers often become common subexpressions. */ 441 if (GET_CODE (x) == PLUS) 442 { 443 rtx constant_term = const0_rtx; 444 rtx y = eliminate_constant_term (x, &constant_term); 445 if (constant_term == const0_rtx 446 || ! memory_address_p (mode, y)) 447 x = force_operand (x, NULL_RTX); 448 else 449 { 450 y = gen_rtx (PLUS, GET_MODE (x), copy_to_reg (y), constant_term); 451 if (! memory_address_p (mode, y)) 452 x = force_operand (x, NULL_RTX); 453 else 454 x = y; 455 } 456 } 457 458 else if (GET_CODE (x) == MULT || GET_CODE (x) == MINUS) 459 x = force_operand (x, NULL_RTX); 460 461 /* If we have a register that's an invalid address, 462 it must be a hard reg of the wrong class. Copy it to a pseudo. */ 463 else if (GET_CODE (x) == REG) 464 x = copy_to_reg (x); 465 466 /* Last resort: copy the value to a register, since 467 the register is a valid address. */ 468 else 469 x = force_reg (Pmode, x); 470 471 goto done; 472 473 win2: 474 x = oldx; 475 win: 476 if (flag_force_addr && ! cse_not_expected && GET_CODE (x) != REG 477 /* Don't copy an addr via a reg if it is one of our stack slots. */ 478 && ! (GET_CODE (x) == PLUS 479 && (XEXP (x, 0) == virtual_stack_vars_rtx 480 || XEXP (x, 0) == virtual_incoming_args_rtx))) 481 { 482 if (general_operand (x, Pmode)) 483 x = force_reg (Pmode, x); 484 else 485 x = force_operand (x, NULL_RTX); 486 } 487 } 488 489 done: 490 491 /* If we didn't change the address, we are done. Otherwise, mark 492 a reg as a pointer if we have REG or REG + CONST_INT. */ 493 if (oldx == x) 494 return x; 495 else if (GET_CODE (x) == REG) 496 mark_reg_pointer (x); 497 else if (GET_CODE (x) == PLUS 498 && GET_CODE (XEXP (x, 0)) == REG 499 && GET_CODE (XEXP (x, 1)) == CONST_INT) 500 mark_reg_pointer (XEXP (x, 0)); 501 502 /* OLDX may have been the address on a temporary. Update the address 503 to indicate that X is now used. */ 504 update_temp_slot_address (oldx, x); 505 506 return x; 507} 508 509/* Like `memory_address' but pretend `flag_force_addr' is 0. */ 510 511rtx 512memory_address_noforce (mode, x) 513 enum machine_mode mode; 514 rtx x; 515{ 516 int ambient_force_addr = flag_force_addr; 517 rtx val; 518 519 flag_force_addr = 0; 520 val = memory_address (mode, x); 521 flag_force_addr = ambient_force_addr; 522 return val; 523} 524 525/* Convert a mem ref into one with a valid memory address. 526 Pass through anything else unchanged. */ 527 528rtx 529validize_mem (ref) 530 rtx ref; 531{ 532 if (GET_CODE (ref) != MEM) 533 return ref; 534 if (memory_address_p (GET_MODE (ref), XEXP (ref, 0))) 535 return ref; 536 /* Don't alter REF itself, since that is probably a stack slot. */ 537 return change_address (ref, GET_MODE (ref), XEXP (ref, 0)); 538} 539 540/* Return a modified copy of X with its memory address copied 541 into a temporary register to protect it from side effects. 542 If X is not a MEM, it is returned unchanged (and not copied). 543 Perhaps even if it is a MEM, if there is no need to change it. */ 544 545rtx 546stabilize (x) 547 rtx x; 548{ 549 register rtx addr; 550 if (GET_CODE (x) != MEM) 551 return x; 552 addr = XEXP (x, 0); 553 if (rtx_unstable_p (addr)) 554 { 555 rtx temp = copy_all_regs (addr); 556 rtx mem; 557 if (GET_CODE (temp) != REG) 558 temp = copy_to_reg (temp); 559 mem = gen_rtx (MEM, GET_MODE (x), temp); 560 561 /* Mark returned memref with in_struct if it's in an array or 562 structure. Copy const and volatile from original memref. */ 563 564 MEM_IN_STRUCT_P (mem) = MEM_IN_STRUCT_P (x) || GET_CODE (addr) == PLUS; 565 RTX_UNCHANGING_P (mem) = RTX_UNCHANGING_P (x); 566 MEM_VOLATILE_P (mem) = MEM_VOLATILE_P (x); 567 return mem; 568 } 569 return x; 570} 571 572/* Copy the value or contents of X to a new temp reg and return that reg. */ 573 574rtx 575copy_to_reg (x) 576 rtx x; 577{ 578 register rtx temp = gen_reg_rtx (GET_MODE (x)); 579 580 /* If not an operand, must be an address with PLUS and MULT so 581 do the computation. */ 582 if (! general_operand (x, VOIDmode)) 583 x = force_operand (x, temp); 584 585 if (x != temp) 586 emit_move_insn (temp, x); 587 588 return temp; 589} 590 591/* Like copy_to_reg but always give the new register mode Pmode 592 in case X is a constant. */ 593 594rtx 595copy_addr_to_reg (x) 596 rtx x; 597{ 598 return copy_to_mode_reg (Pmode, x); 599} 600 601/* Like copy_to_reg but always give the new register mode MODE 602 in case X is a constant. */ 603 604rtx 605copy_to_mode_reg (mode, x) 606 enum machine_mode mode; 607 rtx x; 608{ 609 register rtx temp = gen_reg_rtx (mode); 610 611 /* If not an operand, must be an address with PLUS and MULT so 612 do the computation. */ 613 if (! general_operand (x, VOIDmode)) 614 x = force_operand (x, temp); 615 616 if (GET_MODE (x) != mode && GET_MODE (x) != VOIDmode) 617 abort (); 618 if (x != temp) 619 emit_move_insn (temp, x); 620 return temp; 621} 622 623/* Load X into a register if it is not already one. 624 Use mode MODE for the register. 625 X should be valid for mode MODE, but it may be a constant which 626 is valid for all integer modes; that's why caller must specify MODE. 627 628 The caller must not alter the value in the register we return, 629 since we mark it as a "constant" register. */ 630 631rtx 632force_reg (mode, x) 633 enum machine_mode mode; 634 rtx x; 635{ 636 register rtx temp, insn, set; 637 638 if (GET_CODE (x) == REG) 639 return x; 640 temp = gen_reg_rtx (mode); 641 insn = emit_move_insn (temp, x); 642 643 /* Let optimizers know that TEMP's value never changes 644 and that X can be substituted for it. Don't get confused 645 if INSN set something else (such as a SUBREG of TEMP). */ 646 if (CONSTANT_P (x) 647 && (set = single_set (insn)) != 0 648 && SET_DEST (set) == temp) 649 { 650 rtx note = find_reg_note (insn, REG_EQUAL, NULL_RTX); 651 652 if (note) 653 XEXP (note, 0) = x; 654 else 655 REG_NOTES (insn) = gen_rtx (EXPR_LIST, REG_EQUAL, x, REG_NOTES (insn)); 656 } 657 return temp; 658} 659 660/* If X is a memory ref, copy its contents to a new temp reg and return 661 that reg. Otherwise, return X. */ 662 663rtx 664force_not_mem (x) 665 rtx x; 666{ 667 register rtx temp; 668 if (GET_CODE (x) != MEM || GET_MODE (x) == BLKmode) 669 return x; 670 temp = gen_reg_rtx (GET_MODE (x)); 671 emit_move_insn (temp, x); 672 return temp; 673} 674 675/* Copy X to TARGET (if it's nonzero and a reg) 676 or to a new temp reg and return that reg. 677 MODE is the mode to use for X in case it is a constant. */ 678 679rtx 680copy_to_suggested_reg (x, target, mode) 681 rtx x, target; 682 enum machine_mode mode; 683{ 684 register rtx temp; 685 686 if (target && GET_CODE (target) == REG) 687 temp = target; 688 else 689 temp = gen_reg_rtx (mode); 690 691 emit_move_insn (temp, x); 692 return temp; 693} 694 695/* Return the mode to use to store a scalar of TYPE and MODE. 696 PUNSIGNEDP points to the signedness of the type and may be adjusted 697 to show what signedness to use on extension operations. 698 699 FOR_CALL is non-zero if this call is promoting args for a call. */ 700 701enum machine_mode 702promote_mode (type, mode, punsignedp, for_call) 703 tree type; 704 enum machine_mode mode; 705 int *punsignedp; 706 int for_call; 707{ 708 enum tree_code code = TREE_CODE (type); 709 int unsignedp = *punsignedp; 710 711#ifdef PROMOTE_FOR_CALL_ONLY 712 if (! for_call) 713 return mode; 714#endif 715 716 switch (code) 717 { 718#ifdef PROMOTE_MODE 719 case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE: 720 case CHAR_TYPE: case REAL_TYPE: case OFFSET_TYPE: 721 PROMOTE_MODE (mode, unsignedp, type); 722 break; 723#endif 724 725#ifdef POINTERS_EXTEND_UNSIGNED 726 case POINTER_TYPE: 727 mode = Pmode; 728 unsignedp = POINTERS_EXTEND_UNSIGNED; 729 break; 730#endif 731 } 732 733 *punsignedp = unsignedp; 734 return mode; 735} 736 737/* Adjust the stack pointer by ADJUST (an rtx for a number of bytes). 738 This pops when ADJUST is positive. ADJUST need not be constant. */ 739 740void 741adjust_stack (adjust) 742 rtx adjust; 743{ 744 rtx temp; 745 adjust = protect_from_queue (adjust, 0); 746 747 if (adjust == const0_rtx) 748 return; 749 750 temp = expand_binop (Pmode, 751#ifdef STACK_GROWS_DOWNWARD 752 add_optab, 753#else 754 sub_optab, 755#endif 756 stack_pointer_rtx, adjust, stack_pointer_rtx, 0, 757 OPTAB_LIB_WIDEN); 758 759 if (temp != stack_pointer_rtx) 760 emit_move_insn (stack_pointer_rtx, temp); 761} 762 763/* Adjust the stack pointer by minus ADJUST (an rtx for a number of bytes). 764 This pushes when ADJUST is positive. ADJUST need not be constant. */ 765 766void 767anti_adjust_stack (adjust) 768 rtx adjust; 769{ 770 rtx temp; 771 adjust = protect_from_queue (adjust, 0); 772 773 if (adjust == const0_rtx) 774 return; 775 776 temp = expand_binop (Pmode, 777#ifdef STACK_GROWS_DOWNWARD 778 sub_optab, 779#else 780 add_optab, 781#endif 782 stack_pointer_rtx, adjust, stack_pointer_rtx, 0, 783 OPTAB_LIB_WIDEN); 784 785 if (temp != stack_pointer_rtx) 786 emit_move_insn (stack_pointer_rtx, temp); 787} 788 789/* Round the size of a block to be pushed up to the boundary required 790 by this machine. SIZE is the desired size, which need not be constant. */ 791 792rtx 793round_push (size) 794 rtx size; 795{ 796#ifdef STACK_BOUNDARY 797 int align = STACK_BOUNDARY / BITS_PER_UNIT; 798 if (align == 1) 799 return size; 800 if (GET_CODE (size) == CONST_INT) 801 { 802 int new = (INTVAL (size) + align - 1) / align * align; 803 if (INTVAL (size) != new) 804 size = GEN_INT (new); 805 } 806 else 807 { 808 /* CEIL_DIV_EXPR needs to worry about the addition overflowing, 809 but we know it can't. So add ourselves and then do TRUNC_DIV_EXPR. */ 810 size = expand_binop (Pmode, add_optab, size, GEN_INT (align - 1), 811 NULL_RTX, 1, OPTAB_LIB_WIDEN); 812 size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size, GEN_INT (align), 813 NULL_RTX, 1); 814 size = expand_mult (Pmode, size, GEN_INT (align), NULL_RTX, 1); 815 } 816#endif /* STACK_BOUNDARY */ 817 return size; 818} 819 820/* Save the stack pointer for the purpose in SAVE_LEVEL. PSAVE is a pointer 821 to a previously-created save area. If no save area has been allocated, 822 this function will allocate one. If a save area is specified, it 823 must be of the proper mode. 824 825 The insns are emitted after insn AFTER, if nonzero, otherwise the insns 826 are emitted at the current position. */ 827 828void 829emit_stack_save (save_level, psave, after) 830 enum save_level save_level; 831 rtx *psave; 832 rtx after; 833{ 834 rtx sa = *psave; 835 /* The default is that we use a move insn and save in a Pmode object. */ 836 rtx (*fcn) () = gen_move_insn; 837 enum machine_mode mode = Pmode; 838 839 /* See if this machine has anything special to do for this kind of save. */ 840 switch (save_level) 841 { 842#ifdef HAVE_save_stack_block 843 case SAVE_BLOCK: 844 if (HAVE_save_stack_block) 845 { 846 fcn = gen_save_stack_block; 847 mode = insn_operand_mode[CODE_FOR_save_stack_block][0]; 848 } 849 break; 850#endif 851#ifdef HAVE_save_stack_function 852 case SAVE_FUNCTION: 853 if (HAVE_save_stack_function) 854 { 855 fcn = gen_save_stack_function; 856 mode = insn_operand_mode[CODE_FOR_save_stack_function][0]; 857 } 858 break; 859#endif 860#ifdef HAVE_save_stack_nonlocal 861 case SAVE_NONLOCAL: 862 if (HAVE_save_stack_nonlocal) 863 { 864 fcn = gen_save_stack_nonlocal; 865 mode = insn_operand_mode[(int) CODE_FOR_save_stack_nonlocal][0]; 866 } 867 break; 868#endif 869 } 870 871 /* If there is no save area and we have to allocate one, do so. Otherwise 872 verify the save area is the proper mode. */ 873 874 if (sa == 0) 875 { 876 if (mode != VOIDmode) 877 { 878 if (save_level == SAVE_NONLOCAL) 879 *psave = sa = assign_stack_local (mode, GET_MODE_SIZE (mode), 0); 880 else 881 *psave = sa = gen_reg_rtx (mode); 882 } 883 } 884 else 885 { 886 if (mode == VOIDmode || GET_MODE (sa) != mode) 887 abort (); 888 } 889 890 if (after) 891 { 892 rtx seq; 893 894 start_sequence (); 895 /* We must validize inside the sequence, to ensure that any instructions 896 created by the validize call also get moved to the right place. */ 897 if (sa != 0) 898 sa = validize_mem (sa); 899 emit_insn (fcn (sa, stack_pointer_rtx)); 900 seq = gen_sequence (); 901 end_sequence (); 902 emit_insn_after (seq, after); 903 } 904 else 905 { 906 if (sa != 0) 907 sa = validize_mem (sa); 908 emit_insn (fcn (sa, stack_pointer_rtx)); 909 } 910} 911 912/* Restore the stack pointer for the purpose in SAVE_LEVEL. SA is the save 913 area made by emit_stack_save. If it is zero, we have nothing to do. 914 915 Put any emitted insns after insn AFTER, if nonzero, otherwise at 916 current position. */ 917 918void 919emit_stack_restore (save_level, sa, after) 920 enum save_level save_level; 921 rtx after; 922 rtx sa; 923{ 924 /* The default is that we use a move insn. */ 925 rtx (*fcn) () = gen_move_insn; 926 927 /* See if this machine has anything special to do for this kind of save. */ 928 switch (save_level) 929 { 930#ifdef HAVE_restore_stack_block 931 case SAVE_BLOCK: 932 if (HAVE_restore_stack_block) 933 fcn = gen_restore_stack_block; 934 break; 935#endif 936#ifdef HAVE_restore_stack_function 937 case SAVE_FUNCTION: 938 if (HAVE_restore_stack_function) 939 fcn = gen_restore_stack_function; 940 break; 941#endif 942#ifdef HAVE_restore_stack_nonlocal 943 944 case SAVE_NONLOCAL: 945 if (HAVE_restore_stack_nonlocal) 946 fcn = gen_restore_stack_nonlocal; 947 break; 948#endif 949 } 950 951 if (sa != 0) 952 sa = validize_mem (sa); 953 954 if (after) 955 { 956 rtx seq; 957 958 start_sequence (); 959 emit_insn (fcn (stack_pointer_rtx, sa)); 960 seq = gen_sequence (); 961 end_sequence (); 962 emit_insn_after (seq, after); 963 } 964 else 965 emit_insn (fcn (stack_pointer_rtx, sa)); 966} 967 968/* Return an rtx representing the address of an area of memory dynamically 969 pushed on the stack. This region of memory is always aligned to 970 a multiple of BIGGEST_ALIGNMENT. 971 972 Any required stack pointer alignment is preserved. 973 974 SIZE is an rtx representing the size of the area. 975 TARGET is a place in which the address can be placed. 976 977 KNOWN_ALIGN is the alignment (in bits) that we know SIZE has. */ 978 979rtx 980allocate_dynamic_stack_space (size, target, known_align) 981 rtx size; 982 rtx target; 983 int known_align; 984{ 985 /* If we're asking for zero bytes, it doesn't matter what we point 986 to since we can't dereference it. But return a reasonable 987 address anyway. */ 988 if (size == const0_rtx) 989 return virtual_stack_dynamic_rtx; 990 991 /* Otherwise, show we're calling alloca or equivalent. */ 992 current_function_calls_alloca = 1; 993 994 /* Ensure the size is in the proper mode. */ 995 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode) 996 size = convert_to_mode (Pmode, size, 1); 997 998 /* We will need to ensure that the address we return is aligned to 999 BIGGEST_ALIGNMENT. If STACK_DYNAMIC_OFFSET is defined, we don't 1000 always know its final value at this point in the compilation (it 1001 might depend on the size of the outgoing parameter lists, for 1002 example), so we must align the value to be returned in that case. 1003 (Note that STACK_DYNAMIC_OFFSET will have a default non-zero value if 1004 STACK_POINTER_OFFSET or ACCUMULATE_OUTGOING_ARGS are defined). 1005 We must also do an alignment operation on the returned value if 1006 the stack pointer alignment is less strict that BIGGEST_ALIGNMENT. 1007 1008 If we have to align, we must leave space in SIZE for the hole 1009 that might result from the alignment operation. */ 1010 1011#if defined (STACK_DYNAMIC_OFFSET) || defined (STACK_POINTER_OFFSET) || defined (ALLOCATE_OUTGOING_ARGS) || ! defined (STACK_BOUNDARY) 1012#define MUST_ALIGN 1 1013#else 1014#define MUST_ALIGN (STACK_BOUNDARY < BIGGEST_ALIGNMENT) 1015#endif 1016 1017 if (MUST_ALIGN) 1018 { 1019 if (GET_CODE (size) == CONST_INT) 1020 size = GEN_INT (INTVAL (size) 1021 + (BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1)); 1022 else 1023 size = expand_binop (Pmode, add_optab, size, 1024 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1), 1025 NULL_RTX, 1, OPTAB_LIB_WIDEN); 1026 } 1027 1028#ifdef SETJMP_VIA_SAVE_AREA 1029 /* If setjmp restores regs from a save area in the stack frame, 1030 avoid clobbering the reg save area. Note that the offset of 1031 virtual_incoming_args_rtx includes the preallocated stack args space. 1032 It would be no problem to clobber that, but it's on the wrong side 1033 of the old save area. */ 1034 { 1035 rtx dynamic_offset 1036 = expand_binop (Pmode, sub_optab, virtual_stack_dynamic_rtx, 1037 stack_pointer_rtx, NULL_RTX, 1, OPTAB_LIB_WIDEN); 1038 size = expand_binop (Pmode, add_optab, size, dynamic_offset, 1039 NULL_RTX, 1, OPTAB_LIB_WIDEN); 1040 } 1041#endif /* SETJMP_VIA_SAVE_AREA */ 1042 1043 /* Round the size to a multiple of the required stack alignment. 1044 Since the stack if presumed to be rounded before this allocation, 1045 this will maintain the required alignment. 1046 1047 If the stack grows downward, we could save an insn by subtracting 1048 SIZE from the stack pointer and then aligning the stack pointer. 1049 The problem with this is that the stack pointer may be unaligned 1050 between the execution of the subtraction and alignment insns and 1051 some machines do not allow this. Even on those that do, some 1052 signal handlers malfunction if a signal should occur between those 1053 insns. Since this is an extremely rare event, we have no reliable 1054 way of knowing which systems have this problem. So we avoid even 1055 momentarily mis-aligning the stack. */ 1056 1057#ifdef STACK_BOUNDARY 1058 /* If we added a variable amount to SIZE, 1059 we can no longer assume it is aligned. */ 1060#if !defined (SETJMP_VIA_SAVE_AREA) 1061 if (MUST_ALIGN || known_align % STACK_BOUNDARY != 0) 1062#endif 1063 size = round_push (size); 1064#endif 1065 1066 do_pending_stack_adjust (); 1067 1068 /* Don't use a TARGET that isn't a pseudo. */ 1069 if (target == 0 || GET_CODE (target) != REG 1070 || REGNO (target) < FIRST_PSEUDO_REGISTER) 1071 target = gen_reg_rtx (Pmode); 1072 1073 mark_reg_pointer (target); 1074 1075#ifndef STACK_GROWS_DOWNWARD 1076 emit_move_insn (target, virtual_stack_dynamic_rtx); 1077#endif 1078 1079 /* Perform the required allocation from the stack. Some systems do 1080 this differently than simply incrementing/decrementing from the 1081 stack pointer. */ 1082#ifdef HAVE_allocate_stack 1083 if (HAVE_allocate_stack) 1084 { 1085 enum machine_mode mode 1086 = insn_operand_mode[(int) CODE_FOR_allocate_stack][0]; 1087 1088 size = convert_modes (mode, ptr_mode, size, 1); 1089 1090 if (insn_operand_predicate[(int) CODE_FOR_allocate_stack][0] 1091 && ! ((*insn_operand_predicate[(int) CODE_FOR_allocate_stack][0]) 1092 (size, mode))) 1093 size = copy_to_mode_reg (mode, size); 1094 1095 emit_insn (gen_allocate_stack (size)); 1096 } 1097 else 1098#endif 1099 { 1100 size = convert_modes (Pmode, ptr_mode, size, 1); 1101 anti_adjust_stack (size); 1102 } 1103 1104#ifdef STACK_GROWS_DOWNWARD 1105 emit_move_insn (target, virtual_stack_dynamic_rtx); 1106#endif 1107 1108 if (MUST_ALIGN) 1109 { 1110 /* CEIL_DIV_EXPR needs to worry about the addition overflowing, 1111 but we know it can't. So add ourselves and then do TRUNC_DIV_EXPR. */ 1112 target = expand_binop (Pmode, add_optab, target, 1113 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1), 1114 NULL_RTX, 1, OPTAB_LIB_WIDEN); 1115 target = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, target, 1116 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT), 1117 NULL_RTX, 1); 1118 target = expand_mult (Pmode, target, 1119 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT), 1120 NULL_RTX, 1); 1121 } 1122 1123 /* Some systems require a particular insn to refer to the stack 1124 to make the pages exist. */ 1125#ifdef HAVE_probe 1126 if (HAVE_probe) 1127 emit_insn (gen_probe ()); 1128#endif 1129 1130 /* Record the new stack level for nonlocal gotos. */ 1131 if (nonlocal_goto_handler_slot != 0) 1132 emit_stack_save (SAVE_NONLOCAL, &nonlocal_goto_stack_level, NULL_RTX); 1133 1134 return target; 1135} 1136 1137/* Return an rtx representing the register or memory location 1138 in which a scalar value of data type VALTYPE 1139 was returned by a function call to function FUNC. 1140 FUNC is a FUNCTION_DECL node if the precise function is known, 1141 otherwise 0. */ 1142 1143rtx 1144hard_function_value (valtype, func) 1145 tree valtype; 1146 tree func; 1147{ 1148 rtx val = FUNCTION_VALUE (valtype, func); 1149 if (GET_CODE (val) == REG 1150 && GET_MODE (val) == BLKmode) 1151 { 1152 int bytes = int_size_in_bytes (valtype); 1153 enum machine_mode tmpmode; 1154 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT); 1155 tmpmode != MAX_MACHINE_MODE; 1156 tmpmode = GET_MODE_WIDER_MODE (tmpmode)) 1157 { 1158 /* Have we found a large enough mode? */ 1159 if (GET_MODE_SIZE (tmpmode) >= bytes) 1160 break; 1161 } 1162 1163 /* No suitable mode found. */ 1164 if (tmpmode == MAX_MACHINE_MODE) 1165 abort (); 1166 1167 PUT_MODE (val, tmpmode); 1168 } 1169 return val; 1170} 1171 1172/* Return an rtx representing the register or memory location 1173 in which a scalar value of mode MODE was returned by a library call. */ 1174 1175rtx 1176hard_libcall_value (mode) 1177 enum machine_mode mode; 1178{ 1179 return LIBCALL_VALUE (mode); 1180} 1181 1182/* Look up the tree code for a given rtx code 1183 to provide the arithmetic operation for REAL_ARITHMETIC. 1184 The function returns an int because the caller may not know 1185 what `enum tree_code' means. */ 1186 1187int 1188rtx_to_tree_code (code) 1189 enum rtx_code code; 1190{ 1191 enum tree_code tcode; 1192 1193 switch (code) 1194 { 1195 case PLUS: 1196 tcode = PLUS_EXPR; 1197 break; 1198 case MINUS: 1199 tcode = MINUS_EXPR; 1200 break; 1201 case MULT: 1202 tcode = MULT_EXPR; 1203 break; 1204 case DIV: 1205 tcode = RDIV_EXPR; 1206 break; 1207 case SMIN: 1208 tcode = MIN_EXPR; 1209 break; 1210 case SMAX: 1211 tcode = MAX_EXPR; 1212 break; 1213 default: 1214 tcode = LAST_AND_UNUSED_TREE_CODE; 1215 break; 1216 } 1217 return ((int) tcode); 1218} 1219