1 /* Subroutines for manipulating rtx's in semantically interesting ways. 2 Copyright (C) 1987, 1991, 1994, 1995, 1996, 1997, 1998, 3 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008 4 Free Software Foundation, Inc. 5 6 This file is part of GCC. 7 8 GCC is free software; you can redistribute it and/or modify it under 9 the terms of the GNU General Public License as published by the Free 10 Software Foundation; either version 3, or (at your option) any later 11 version. 12 13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY 14 WARRANTY; without even the implied warranty of MERCHANTABILITY or 15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 16 for more details. 17 18 You should have received a copy of the GNU General Public License 19 along with GCC; see the file COPYING3. If not see 20 <http://www.gnu.org/licenses/>. */ 21 22 23 #include "config.h" 24 #include "system.h" 25 #include "coretypes.h" 26 #include "tm.h" 27 #include "toplev.h" 28 #include "rtl.h" 29 #include "tree.h" 30 #include "tm_p.h" 31 #include "flags.h" 32 #include "except.h" 33 #include "function.h" 34 #include "expr.h" 35 #include "optabs.h" 36 #include "hard-reg-set.h" 37 #include "insn-config.h" 38 #include "ggc.h" 39 #include "recog.h" 40 #include "langhooks.h" 41 #include "target.h" 42 #include "output.h" 43 44 static rtx break_out_memory_refs (rtx); 45 static void emit_stack_probe (rtx); 46 47 48 /* Truncate and perhaps sign-extend C as appropriate for MODE. */ 49 50 HOST_WIDE_INT 51 trunc_int_for_mode (HOST_WIDE_INT c, enum machine_mode mode) 52 { 53 int width = GET_MODE_BITSIZE (mode); 54 55 /* You want to truncate to a _what_? */ 56 gcc_assert (SCALAR_INT_MODE_P (mode)); 57 58 /* Canonicalize BImode to 0 and STORE_FLAG_VALUE. */ 59 if (mode == BImode) 60 return c & 1 ? STORE_FLAG_VALUE : 0; 61 62 /* Sign-extend for the requested mode. */ 63 64 if (width < HOST_BITS_PER_WIDE_INT) 65 { 66 HOST_WIDE_INT sign = 1; 67 sign <<= width - 1; 68 c &= (sign << 1) - 1; 69 c ^= sign; 70 c -= sign; 71 } 72 73 return c; 74 } 75 76 /* Return an rtx for the sum of X and the integer C. */ 77 78 rtx 79 plus_constant (rtx x, HOST_WIDE_INT c) 80 { 81 RTX_CODE code; 82 rtx y; 83 enum machine_mode mode; 84 rtx tem; 85 int all_constant = 0; 86 87 if (c == 0) 88 return x; 89 90 restart: 91 92 code = GET_CODE (x); 93 mode = GET_MODE (x); 94 y = x; 95 96 switch (code) 97 { 98 case CONST_INT: 99 return GEN_INT (INTVAL (x) + c); 100 101 case CONST_DOUBLE: 102 { 103 unsigned HOST_WIDE_INT l1 = CONST_DOUBLE_LOW (x); 104 HOST_WIDE_INT h1 = CONST_DOUBLE_HIGH (x); 105 unsigned HOST_WIDE_INT l2 = c; 106 HOST_WIDE_INT h2 = c < 0 ? ~0 : 0; 107 unsigned HOST_WIDE_INT lv; 108 HOST_WIDE_INT hv; 109 110 add_double (l1, h1, l2, h2, &lv, &hv); 111 112 return immed_double_const (lv, hv, VOIDmode); 113 } 114 115 case MEM: 116 /* If this is a reference to the constant pool, try replacing it with 117 a reference to a new constant. If the resulting address isn't 118 valid, don't return it because we have no way to validize it. */ 119 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF 120 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0))) 121 { 122 tem 123 = force_const_mem (GET_MODE (x), 124 plus_constant (get_pool_constant (XEXP (x, 0)), 125 c)); 126 if (memory_address_p (GET_MODE (tem), XEXP (tem, 0))) 127 return tem; 128 } 129 break; 130 131 case CONST: 132 /* If adding to something entirely constant, set a flag 133 so that we can add a CONST around the result. */ 134 x = XEXP (x, 0); 135 all_constant = 1; 136 goto restart; 137 138 case SYMBOL_REF: 139 case LABEL_REF: 140 all_constant = 1; 141 break; 142 143 case PLUS: 144 /* The interesting case is adding the integer to a sum. 145 Look for constant term in the sum and combine 146 with C. For an integer constant term, we make a combined 147 integer. For a constant term that is not an explicit integer, 148 we cannot really combine, but group them together anyway. 149 150 Restart or use a recursive call in case the remaining operand is 151 something that we handle specially, such as a SYMBOL_REF. 152 153 We may not immediately return from the recursive call here, lest 154 all_constant gets lost. */ 155 156 if (CONST_INT_P (XEXP (x, 1))) 157 { 158 c += INTVAL (XEXP (x, 1)); 159 160 if (GET_MODE (x) != VOIDmode) 161 c = trunc_int_for_mode (c, GET_MODE (x)); 162 163 x = XEXP (x, 0); 164 goto restart; 165 } 166 else if (CONSTANT_P (XEXP (x, 1))) 167 { 168 x = gen_rtx_PLUS (mode, XEXP (x, 0), plus_constant (XEXP (x, 1), c)); 169 c = 0; 170 } 171 else if (find_constant_term_loc (&y)) 172 { 173 /* We need to be careful since X may be shared and we can't 174 modify it in place. */ 175 rtx copy = copy_rtx (x); 176 rtx *const_loc = find_constant_term_loc (©); 177 178 *const_loc = plus_constant (*const_loc, c); 179 x = copy; 180 c = 0; 181 } 182 break; 183 184 default: 185 break; 186 } 187 188 if (c != 0) 189 x = gen_rtx_PLUS (mode, x, GEN_INT (c)); 190 191 if (GET_CODE (x) == SYMBOL_REF || GET_CODE (x) == LABEL_REF) 192 return x; 193 else if (all_constant) 194 return gen_rtx_CONST (mode, x); 195 else 196 return x; 197 } 198 199 /* If X is a sum, return a new sum like X but lacking any constant terms. 200 Add all the removed constant terms into *CONSTPTR. 201 X itself is not altered. The result != X if and only if 202 it is not isomorphic to X. */ 203 204 rtx 205 eliminate_constant_term (rtx x, rtx *constptr) 206 { 207 rtx x0, x1; 208 rtx tem; 209 210 if (GET_CODE (x) != PLUS) 211 return x; 212 213 /* First handle constants appearing at this level explicitly. */ 214 if (CONST_INT_P (XEXP (x, 1)) 215 && 0 != (tem = simplify_binary_operation (PLUS, GET_MODE (x), *constptr, 216 XEXP (x, 1))) 217 && CONST_INT_P (tem)) 218 { 219 *constptr = tem; 220 return eliminate_constant_term (XEXP (x, 0), constptr); 221 } 222 223 tem = const0_rtx; 224 x0 = eliminate_constant_term (XEXP (x, 0), &tem); 225 x1 = eliminate_constant_term (XEXP (x, 1), &tem); 226 if ((x1 != XEXP (x, 1) || x0 != XEXP (x, 0)) 227 && 0 != (tem = simplify_binary_operation (PLUS, GET_MODE (x), 228 *constptr, tem)) 229 && CONST_INT_P (tem)) 230 { 231 *constptr = tem; 232 return gen_rtx_PLUS (GET_MODE (x), x0, x1); 233 } 234 235 return x; 236 } 237 238 /* Return an rtx for the size in bytes of the value of EXP. */ 239 240 rtx 241 expr_size (tree exp) 242 { 243 tree size; 244 245 if (TREE_CODE (exp) == WITH_SIZE_EXPR) 246 size = TREE_OPERAND (exp, 1); 247 else 248 { 249 size = tree_expr_size (exp); 250 gcc_assert (size); 251 gcc_assert (size == SUBSTITUTE_PLACEHOLDER_IN_EXPR (size, exp)); 252 } 253 254 return expand_expr (size, NULL_RTX, TYPE_MODE (sizetype), EXPAND_NORMAL); 255 } 256 257 /* Return a wide integer for the size in bytes of the value of EXP, or -1 258 if the size can vary or is larger than an integer. */ 259 260 HOST_WIDE_INT 261 int_expr_size (tree exp) 262 { 263 tree size; 264 265 if (TREE_CODE (exp) == WITH_SIZE_EXPR) 266 size = TREE_OPERAND (exp, 1); 267 else 268 { 269 size = tree_expr_size (exp); 270 gcc_assert (size); 271 } 272 273 if (size == 0 || !host_integerp (size, 0)) 274 return -1; 275 276 return tree_low_cst (size, 0); 277 } 278 279 /* Return a copy of X in which all memory references 280 and all constants that involve symbol refs 281 have been replaced with new temporary registers. 282 Also emit code to load the memory locations and constants 283 into those registers. 284 285 If X contains no such constants or memory references, 286 X itself (not a copy) is returned. 287 288 If a constant is found in the address that is not a legitimate constant 289 in an insn, it is left alone in the hope that it might be valid in the 290 address. 291 292 X may contain no arithmetic except addition, subtraction and multiplication. 293 Values returned by expand_expr with 1 for sum_ok fit this constraint. */ 294 295 static rtx 296 break_out_memory_refs (rtx x) 297 { 298 if (MEM_P (x) 299 || (CONSTANT_P (x) && CONSTANT_ADDRESS_P (x) 300 && GET_MODE (x) != VOIDmode)) 301 x = force_reg (GET_MODE (x), x); 302 else if (GET_CODE (x) == PLUS || GET_CODE (x) == MINUS 303 || GET_CODE (x) == MULT) 304 { 305 rtx op0 = break_out_memory_refs (XEXP (x, 0)); 306 rtx op1 = break_out_memory_refs (XEXP (x, 1)); 307 308 if (op0 != XEXP (x, 0) || op1 != XEXP (x, 1)) 309 x = simplify_gen_binary (GET_CODE (x), GET_MODE (x), op0, op1); 310 } 311 312 return x; 313 } 314 315 /* Given X, a memory address in address space AS' pointer mode, convert it to 316 an address in the address space's address mode, or vice versa (TO_MODE says 317 which way). We take advantage of the fact that pointers are not allowed to 318 overflow by commuting arithmetic operations over conversions so that address 319 arithmetic insns can be used. */ 320 321 rtx 322 convert_memory_address_addr_space (enum machine_mode to_mode ATTRIBUTE_UNUSED, 323 rtx x, addr_space_t as ATTRIBUTE_UNUSED) 324 { 325 #ifndef POINTERS_EXTEND_UNSIGNED 326 gcc_assert (GET_MODE (x) == to_mode || GET_MODE (x) == VOIDmode); 327 return x; 328 #else /* defined(POINTERS_EXTEND_UNSIGNED) */ 329 enum machine_mode pointer_mode, address_mode, from_mode; 330 rtx temp; 331 enum rtx_code code; 332 333 /* If X already has the right mode, just return it. */ 334 if (GET_MODE (x) == to_mode) 335 return x; 336 337 pointer_mode = targetm.addr_space.pointer_mode (as); 338 address_mode = targetm.addr_space.address_mode (as); 339 from_mode = to_mode == pointer_mode ? address_mode : pointer_mode; 340 341 /* Here we handle some special cases. If none of them apply, fall through 342 to the default case. */ 343 switch (GET_CODE (x)) 344 { 345 case CONST_INT: 346 case CONST_DOUBLE: 347 if (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (from_mode)) 348 code = TRUNCATE; 349 else if (POINTERS_EXTEND_UNSIGNED < 0) 350 break; 351 else if (POINTERS_EXTEND_UNSIGNED > 0) 352 code = ZERO_EXTEND; 353 else 354 code = SIGN_EXTEND; 355 temp = simplify_unary_operation (code, to_mode, x, from_mode); 356 if (temp) 357 return temp; 358 break; 359 360 case SUBREG: 361 if ((SUBREG_PROMOTED_VAR_P (x) || REG_POINTER (SUBREG_REG (x))) 362 && GET_MODE (SUBREG_REG (x)) == to_mode) 363 return SUBREG_REG (x); 364 break; 365 366 case LABEL_REF: 367 temp = gen_rtx_LABEL_REF (to_mode, XEXP (x, 0)); 368 LABEL_REF_NONLOCAL_P (temp) = LABEL_REF_NONLOCAL_P (x); 369 return temp; 370 break; 371 372 case SYMBOL_REF: 373 temp = shallow_copy_rtx (x); 374 PUT_MODE (temp, to_mode); 375 return temp; 376 break; 377 378 case CONST: 379 return gen_rtx_CONST (to_mode, 380 convert_memory_address_addr_space 381 (to_mode, XEXP (x, 0), as)); 382 break; 383 384 case PLUS: 385 case MULT: 386 /* For addition we can safely permute the conversion and addition 387 operation if one operand is a constant and converting the constant 388 does not change it or if one operand is a constant and we are 389 using a ptr_extend instruction (POINTERS_EXTEND_UNSIGNED < 0). 390 We can always safely permute them if we are making the address 391 narrower. */ 392 if (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (from_mode) 393 || (GET_CODE (x) == PLUS 394 && CONST_INT_P (XEXP (x, 1)) 395 && (XEXP (x, 1) == convert_memory_address_addr_space 396 (to_mode, XEXP (x, 1), as) 397 || POINTERS_EXTEND_UNSIGNED < 0))) 398 return gen_rtx_fmt_ee (GET_CODE (x), to_mode, 399 convert_memory_address_addr_space 400 (to_mode, XEXP (x, 0), as), 401 XEXP (x, 1)); 402 break; 403 404 default: 405 break; 406 } 407 408 return convert_modes (to_mode, from_mode, 409 x, POINTERS_EXTEND_UNSIGNED); 410 #endif /* defined(POINTERS_EXTEND_UNSIGNED) */ 411 } 412 413 /* Return something equivalent to X but valid as a memory address for something 414 of mode MODE in the named address space AS. When X is not itself valid, 415 this works by copying X or subexpressions of it into registers. */ 416 417 rtx 418 memory_address_addr_space (enum machine_mode mode, rtx x, addr_space_t as) 419 { 420 rtx oldx = x; 421 enum machine_mode address_mode = targetm.addr_space.address_mode (as); 422 423 x = convert_memory_address_addr_space (address_mode, x, as); 424 425 /* By passing constant addresses through registers 426 we get a chance to cse them. */ 427 if (! cse_not_expected && CONSTANT_P (x) && CONSTANT_ADDRESS_P (x)) 428 x = force_reg (address_mode, x); 429 430 /* We get better cse by rejecting indirect addressing at this stage. 431 Let the combiner create indirect addresses where appropriate. 432 For now, generate the code so that the subexpressions useful to share 433 are visible. But not if cse won't be done! */ 434 else 435 { 436 if (! cse_not_expected && !REG_P (x)) 437 x = break_out_memory_refs (x); 438 439 /* At this point, any valid address is accepted. */ 440 if (memory_address_addr_space_p (mode, x, as)) 441 goto done; 442 443 /* If it was valid before but breaking out memory refs invalidated it, 444 use it the old way. */ 445 if (memory_address_addr_space_p (mode, oldx, as)) 446 { 447 x = oldx; 448 goto done; 449 } 450 451 /* Perform machine-dependent transformations on X 452 in certain cases. This is not necessary since the code 453 below can handle all possible cases, but machine-dependent 454 transformations can make better code. */ 455 { 456 rtx orig_x = x; 457 x = targetm.addr_space.legitimize_address (x, oldx, mode, as); 458 if (orig_x != x && memory_address_addr_space_p (mode, x, as)) 459 goto done; 460 } 461 462 /* PLUS and MULT can appear in special ways 463 as the result of attempts to make an address usable for indexing. 464 Usually they are dealt with by calling force_operand, below. 465 But a sum containing constant terms is special 466 if removing them makes the sum a valid address: 467 then we generate that address in a register 468 and index off of it. We do this because it often makes 469 shorter code, and because the addresses thus generated 470 in registers often become common subexpressions. */ 471 if (GET_CODE (x) == PLUS) 472 { 473 rtx constant_term = const0_rtx; 474 rtx y = eliminate_constant_term (x, &constant_term); 475 if (constant_term == const0_rtx 476 || ! memory_address_addr_space_p (mode, y, as)) 477 x = force_operand (x, NULL_RTX); 478 else 479 { 480 y = gen_rtx_PLUS (GET_MODE (x), copy_to_reg (y), constant_term); 481 if (! memory_address_addr_space_p (mode, y, as)) 482 x = force_operand (x, NULL_RTX); 483 else 484 x = y; 485 } 486 } 487 488 else if (GET_CODE (x) == MULT || GET_CODE (x) == MINUS) 489 x = force_operand (x, NULL_RTX); 490 491 /* If we have a register that's an invalid address, 492 it must be a hard reg of the wrong class. Copy it to a pseudo. */ 493 else if (REG_P (x)) 494 x = copy_to_reg (x); 495 496 /* Last resort: copy the value to a register, since 497 the register is a valid address. */ 498 else 499 x = force_reg (address_mode, x); 500 } 501 502 done: 503 504 gcc_assert (memory_address_addr_space_p (mode, x, as)); 505 /* If we didn't change the address, we are done. Otherwise, mark 506 a reg as a pointer if we have REG or REG + CONST_INT. */ 507 if (oldx == x) 508 return x; 509 else if (REG_P (x)) 510 mark_reg_pointer (x, BITS_PER_UNIT); 511 else if (GET_CODE (x) == PLUS 512 && REG_P (XEXP (x, 0)) 513 && CONST_INT_P (XEXP (x, 1))) 514 mark_reg_pointer (XEXP (x, 0), BITS_PER_UNIT); 515 516 /* OLDX may have been the address on a temporary. Update the address 517 to indicate that X is now used. */ 518 update_temp_slot_address (oldx, x); 519 520 return x; 521 } 522 523 /* Convert a mem ref into one with a valid memory address. 524 Pass through anything else unchanged. */ 525 526 rtx 527 validize_mem (rtx ref) 528 { 529 if (!MEM_P (ref)) 530 return ref; 531 ref = use_anchored_address (ref); 532 if (memory_address_addr_space_p (GET_MODE (ref), XEXP (ref, 0), 533 MEM_ADDR_SPACE (ref))) 534 return ref; 535 536 /* Don't alter REF itself, since that is probably a stack slot. */ 537 return replace_equiv_address (ref, XEXP (ref, 0)); 538 } 539 540 /* If X is a memory reference to a member of an object block, try rewriting 541 it to use an anchor instead. Return the new memory reference on success 542 and the old one on failure. */ 543 544 rtx 545 use_anchored_address (rtx x) 546 { 547 rtx base; 548 HOST_WIDE_INT offset; 549 550 if (!flag_section_anchors) 551 return x; 552 553 if (!MEM_P (x)) 554 return x; 555 556 /* Split the address into a base and offset. */ 557 base = XEXP (x, 0); 558 offset = 0; 559 if (GET_CODE (base) == CONST 560 && GET_CODE (XEXP (base, 0)) == PLUS 561 && CONST_INT_P (XEXP (XEXP (base, 0), 1))) 562 { 563 offset += INTVAL (XEXP (XEXP (base, 0), 1)); 564 base = XEXP (XEXP (base, 0), 0); 565 } 566 567 /* Check whether BASE is suitable for anchors. */ 568 if (GET_CODE (base) != SYMBOL_REF 569 || !SYMBOL_REF_HAS_BLOCK_INFO_P (base) 570 || SYMBOL_REF_ANCHOR_P (base) 571 || SYMBOL_REF_BLOCK (base) == NULL 572 || !targetm.use_anchors_for_symbol_p (base)) 573 return x; 574 575 /* Decide where BASE is going to be. */ 576 place_block_symbol (base); 577 578 /* Get the anchor we need to use. */ 579 offset += SYMBOL_REF_BLOCK_OFFSET (base); 580 base = get_section_anchor (SYMBOL_REF_BLOCK (base), offset, 581 SYMBOL_REF_TLS_MODEL (base)); 582 583 /* Work out the offset from the anchor. */ 584 offset -= SYMBOL_REF_BLOCK_OFFSET (base); 585 586 /* If we're going to run a CSE pass, force the anchor into a register. 587 We will then be able to reuse registers for several accesses, if the 588 target costs say that that's worthwhile. */ 589 if (!cse_not_expected) 590 base = force_reg (GET_MODE (base), base); 591 592 return replace_equiv_address (x, plus_constant (base, offset)); 593 } 594 595 /* Copy the value or contents of X to a new temp reg and return that reg. */ 596 597 rtx 598 copy_to_reg (rtx x) 599 { 600 rtx temp = gen_reg_rtx (GET_MODE (x)); 601 602 /* If not an operand, must be an address with PLUS and MULT so 603 do the computation. */ 604 if (! general_operand (x, VOIDmode)) 605 x = force_operand (x, temp); 606 607 if (x != temp) 608 emit_move_insn (temp, x); 609 610 return temp; 611 } 612 613 /* Like copy_to_reg but always give the new register mode Pmode 614 in case X is a constant. */ 615 616 rtx 617 copy_addr_to_reg (rtx x) 618 { 619 return copy_to_mode_reg (Pmode, x); 620 } 621 622 /* Like copy_to_reg but always give the new register mode MODE 623 in case X is a constant. */ 624 625 rtx 626 copy_to_mode_reg (enum machine_mode mode, rtx x) 627 { 628 rtx temp = gen_reg_rtx (mode); 629 630 /* If not an operand, must be an address with PLUS and MULT so 631 do the computation. */ 632 if (! general_operand (x, VOIDmode)) 633 x = force_operand (x, temp); 634 635 gcc_assert (GET_MODE (x) == mode || GET_MODE (x) == VOIDmode); 636 if (x != temp) 637 emit_move_insn (temp, x); 638 return temp; 639 } 640 641 /* Load X into a register if it is not already one. 642 Use mode MODE for the register. 643 X should be valid for mode MODE, but it may be a constant which 644 is valid for all integer modes; that's why caller must specify MODE. 645 646 The caller must not alter the value in the register we return, 647 since we mark it as a "constant" register. */ 648 649 rtx 650 force_reg (enum machine_mode mode, rtx x) 651 { 652 rtx temp, insn, set; 653 654 if (REG_P (x)) 655 return x; 656 657 if (general_operand (x, mode)) 658 { 659 temp = gen_reg_rtx (mode); 660 insn = emit_move_insn (temp, x); 661 } 662 else 663 { 664 temp = force_operand (x, NULL_RTX); 665 if (REG_P (temp)) 666 insn = get_last_insn (); 667 else 668 { 669 rtx temp2 = gen_reg_rtx (mode); 670 insn = emit_move_insn (temp2, temp); 671 temp = temp2; 672 } 673 } 674 675 /* Let optimizers know that TEMP's value never changes 676 and that X can be substituted for it. Don't get confused 677 if INSN set something else (such as a SUBREG of TEMP). */ 678 if (CONSTANT_P (x) 679 && (set = single_set (insn)) != 0 680 && SET_DEST (set) == temp 681 && ! rtx_equal_p (x, SET_SRC (set))) 682 set_unique_reg_note (insn, REG_EQUAL, x); 683 684 /* Let optimizers know that TEMP is a pointer, and if so, the 685 known alignment of that pointer. */ 686 { 687 unsigned align = 0; 688 if (GET_CODE (x) == SYMBOL_REF) 689 { 690 align = BITS_PER_UNIT; 691 if (SYMBOL_REF_DECL (x) && DECL_P (SYMBOL_REF_DECL (x))) 692 align = DECL_ALIGN (SYMBOL_REF_DECL (x)); 693 } 694 else if (GET_CODE (x) == LABEL_REF) 695 align = BITS_PER_UNIT; 696 else if (GET_CODE (x) == CONST 697 && GET_CODE (XEXP (x, 0)) == PLUS 698 && GET_CODE (XEXP (XEXP (x, 0), 0)) == SYMBOL_REF 699 && CONST_INT_P (XEXP (XEXP (x, 0), 1))) 700 { 701 rtx s = XEXP (XEXP (x, 0), 0); 702 rtx c = XEXP (XEXP (x, 0), 1); 703 unsigned sa, ca; 704 705 sa = BITS_PER_UNIT; 706 if (SYMBOL_REF_DECL (s) && DECL_P (SYMBOL_REF_DECL (s))) 707 sa = DECL_ALIGN (SYMBOL_REF_DECL (s)); 708 709 ca = exact_log2 (INTVAL (c) & -INTVAL (c)) * BITS_PER_UNIT; 710 711 align = MIN (sa, ca); 712 } 713 714 if (align || (MEM_P (x) && MEM_POINTER (x))) 715 mark_reg_pointer (temp, align); 716 } 717 718 return temp; 719 } 720 721 /* If X is a memory ref, copy its contents to a new temp reg and return 722 that reg. Otherwise, return X. */ 723 724 rtx 725 force_not_mem (rtx x) 726 { 727 rtx temp; 728 729 if (!MEM_P (x) || GET_MODE (x) == BLKmode) 730 return x; 731 732 temp = gen_reg_rtx (GET_MODE (x)); 733 734 if (MEM_POINTER (x)) 735 REG_POINTER (temp) = 1; 736 737 emit_move_insn (temp, x); 738 return temp; 739 } 740 741 /* Copy X to TARGET (if it's nonzero and a reg) 742 or to a new temp reg and return that reg. 743 MODE is the mode to use for X in case it is a constant. */ 744 745 rtx 746 copy_to_suggested_reg (rtx x, rtx target, enum machine_mode mode) 747 { 748 rtx temp; 749 750 if (target && REG_P (target)) 751 temp = target; 752 else 753 temp = gen_reg_rtx (mode); 754 755 emit_move_insn (temp, x); 756 return temp; 757 } 758 759 /* Return the mode to use to pass or return a scalar of TYPE and MODE. 760 PUNSIGNEDP points to the signedness of the type and may be adjusted 761 to show what signedness to use on extension operations. 762 763 FOR_RETURN is nonzero if the caller is promoting the return value 764 of FNDECL, else it is for promoting args. */ 765 766 enum machine_mode 767 promote_function_mode (const_tree type, enum machine_mode mode, int *punsignedp, 768 const_tree funtype, int for_return) 769 { 770 switch (TREE_CODE (type)) 771 { 772 case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE: 773 case REAL_TYPE: case OFFSET_TYPE: case FIXED_POINT_TYPE: 774 case POINTER_TYPE: case REFERENCE_TYPE: 775 return targetm.calls.promote_function_mode (type, mode, punsignedp, funtype, 776 for_return); 777 778 default: 779 return mode; 780 } 781 } 782 /* Return the mode to use to store a scalar of TYPE and MODE. 783 PUNSIGNEDP points to the signedness of the type and may be adjusted 784 to show what signedness to use on extension operations. */ 785 786 enum machine_mode 787 promote_mode (const_tree type ATTRIBUTE_UNUSED, enum machine_mode mode, 788 int *punsignedp ATTRIBUTE_UNUSED) 789 { 790 /* FIXME: this is the same logic that was there until GCC 4.4, but we 791 probably want to test POINTERS_EXTEND_UNSIGNED even if PROMOTE_MODE 792 is not defined. The affected targets are M32C, S390, SPARC. */ 793 #ifdef PROMOTE_MODE 794 const enum tree_code code = TREE_CODE (type); 795 int unsignedp = *punsignedp; 796 797 switch (code) 798 { 799 case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE: 800 case REAL_TYPE: case OFFSET_TYPE: case FIXED_POINT_TYPE: 801 PROMOTE_MODE (mode, unsignedp, type); 802 *punsignedp = unsignedp; 803 return mode; 804 break; 805 806 #ifdef POINTERS_EXTEND_UNSIGNED 807 case REFERENCE_TYPE: 808 case POINTER_TYPE: 809 *punsignedp = POINTERS_EXTEND_UNSIGNED; 810 return targetm.addr_space.address_mode 811 (TYPE_ADDR_SPACE (TREE_TYPE (type))); 812 break; 813 #endif 814 815 default: 816 return mode; 817 } 818 #else 819 return mode; 820 #endif 821 } 822 823 824 /* Use one of promote_mode or promote_function_mode to find the promoted 825 mode of DECL. If PUNSIGNEDP is not NULL, store there the unsignedness 826 of DECL after promotion. */ 827 828 enum machine_mode 829 promote_decl_mode (const_tree decl, int *punsignedp) 830 { 831 tree type = TREE_TYPE (decl); 832 int unsignedp = TYPE_UNSIGNED (type); 833 enum machine_mode mode = DECL_MODE (decl); 834 enum machine_mode pmode; 835 836 if (TREE_CODE (decl) == RESULT_DECL 837 || TREE_CODE (decl) == PARM_DECL) 838 pmode = promote_function_mode (type, mode, &unsignedp, 839 TREE_TYPE (current_function_decl), 2); 840 else 841 pmode = promote_mode (type, mode, &unsignedp); 842 843 if (punsignedp) 844 *punsignedp = unsignedp; 845 return pmode; 846 } 847 848 849 /* Adjust the stack pointer by ADJUST (an rtx for a number of bytes). 850 This pops when ADJUST is positive. ADJUST need not be constant. */ 851 852 void 853 adjust_stack (rtx adjust) 854 { 855 rtx temp; 856 857 if (adjust == const0_rtx) 858 return; 859 860 /* We expect all variable sized adjustments to be multiple of 861 PREFERRED_STACK_BOUNDARY. */ 862 if (CONST_INT_P (adjust)) 863 stack_pointer_delta -= INTVAL (adjust); 864 865 temp = expand_binop (Pmode, 866 #ifdef STACK_GROWS_DOWNWARD 867 add_optab, 868 #else 869 sub_optab, 870 #endif 871 stack_pointer_rtx, adjust, stack_pointer_rtx, 0, 872 OPTAB_LIB_WIDEN); 873 874 if (temp != stack_pointer_rtx) 875 emit_move_insn (stack_pointer_rtx, temp); 876 } 877 878 /* Adjust the stack pointer by minus ADJUST (an rtx for a number of bytes). 879 This pushes when ADJUST is positive. ADJUST need not be constant. */ 880 881 void 882 anti_adjust_stack (rtx adjust) 883 { 884 rtx temp; 885 886 if (adjust == const0_rtx) 887 return; 888 889 /* We expect all variable sized adjustments to be multiple of 890 PREFERRED_STACK_BOUNDARY. */ 891 if (CONST_INT_P (adjust)) 892 stack_pointer_delta += INTVAL (adjust); 893 894 temp = expand_binop (Pmode, 895 #ifdef STACK_GROWS_DOWNWARD 896 sub_optab, 897 #else 898 add_optab, 899 #endif 900 stack_pointer_rtx, adjust, stack_pointer_rtx, 0, 901 OPTAB_LIB_WIDEN); 902 903 if (temp != stack_pointer_rtx) 904 emit_move_insn (stack_pointer_rtx, temp); 905 } 906 907 /* Round the size of a block to be pushed up to the boundary required 908 by this machine. SIZE is the desired size, which need not be constant. */ 909 910 static rtx 911 round_push (rtx size) 912 { 913 int align = PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT; 914 915 if (align == 1) 916 return size; 917 918 if (CONST_INT_P (size)) 919 { 920 HOST_WIDE_INT new_size = (INTVAL (size) + align - 1) / align * align; 921 922 if (INTVAL (size) != new_size) 923 size = GEN_INT (new_size); 924 } 925 else 926 { 927 /* CEIL_DIV_EXPR needs to worry about the addition overflowing, 928 but we know it can't. So add ourselves and then do 929 TRUNC_DIV_EXPR. */ 930 size = expand_binop (Pmode, add_optab, size, GEN_INT (align - 1), 931 NULL_RTX, 1, OPTAB_LIB_WIDEN); 932 size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size, GEN_INT (align), 933 NULL_RTX, 1); 934 size = expand_mult (Pmode, size, GEN_INT (align), NULL_RTX, 1); 935 } 936 937 return size; 938 } 939 940 /* Save the stack pointer for the purpose in SAVE_LEVEL. PSAVE is a pointer 941 to a previously-created save area. If no save area has been allocated, 942 this function will allocate one. If a save area is specified, it 943 must be of the proper mode. 944 945 The insns are emitted after insn AFTER, if nonzero, otherwise the insns 946 are emitted at the current position. */ 947 948 void 949 emit_stack_save (enum save_level save_level, rtx *psave, rtx after) 950 { 951 rtx sa = *psave; 952 /* The default is that we use a move insn and save in a Pmode object. */ 953 rtx (*fcn) (rtx, rtx) = gen_move_insn; 954 enum machine_mode mode = STACK_SAVEAREA_MODE (save_level); 955 956 /* See if this machine has anything special to do for this kind of save. */ 957 switch (save_level) 958 { 959 #ifdef HAVE_save_stack_block 960 case SAVE_BLOCK: 961 if (HAVE_save_stack_block) 962 fcn = gen_save_stack_block; 963 break; 964 #endif 965 #ifdef HAVE_save_stack_function 966 case SAVE_FUNCTION: 967 if (HAVE_save_stack_function) 968 fcn = gen_save_stack_function; 969 break; 970 #endif 971 #ifdef HAVE_save_stack_nonlocal 972 case SAVE_NONLOCAL: 973 if (HAVE_save_stack_nonlocal) 974 fcn = gen_save_stack_nonlocal; 975 break; 976 #endif 977 default: 978 break; 979 } 980 981 /* If there is no save area and we have to allocate one, do so. Otherwise 982 verify the save area is the proper mode. */ 983 984 if (sa == 0) 985 { 986 if (mode != VOIDmode) 987 { 988 if (save_level == SAVE_NONLOCAL) 989 *psave = sa = assign_stack_local (mode, GET_MODE_SIZE (mode), 0); 990 else 991 *psave = sa = gen_reg_rtx (mode); 992 } 993 } 994 995 if (after) 996 { 997 rtx seq; 998 999 start_sequence (); 1000 do_pending_stack_adjust (); 1001 /* We must validize inside the sequence, to ensure that any instructions 1002 created by the validize call also get moved to the right place. */ 1003 if (sa != 0) 1004 sa = validize_mem (sa); 1005 emit_insn (fcn (sa, stack_pointer_rtx)); 1006 seq = get_insns (); 1007 end_sequence (); 1008 emit_insn_after (seq, after); 1009 } 1010 else 1011 { 1012 do_pending_stack_adjust (); 1013 if (sa != 0) 1014 sa = validize_mem (sa); 1015 emit_insn (fcn (sa, stack_pointer_rtx)); 1016 } 1017 } 1018 1019 /* Restore the stack pointer for the purpose in SAVE_LEVEL. SA is the save 1020 area made by emit_stack_save. If it is zero, we have nothing to do. 1021 1022 Put any emitted insns after insn AFTER, if nonzero, otherwise at 1023 current position. */ 1024 1025 void 1026 emit_stack_restore (enum save_level save_level, rtx sa, rtx after) 1027 { 1028 /* The default is that we use a move insn. */ 1029 rtx (*fcn) (rtx, rtx) = gen_move_insn; 1030 1031 /* See if this machine has anything special to do for this kind of save. */ 1032 switch (save_level) 1033 { 1034 #ifdef HAVE_restore_stack_block 1035 case SAVE_BLOCK: 1036 if (HAVE_restore_stack_block) 1037 fcn = gen_restore_stack_block; 1038 break; 1039 #endif 1040 #ifdef HAVE_restore_stack_function 1041 case SAVE_FUNCTION: 1042 if (HAVE_restore_stack_function) 1043 fcn = gen_restore_stack_function; 1044 break; 1045 #endif 1046 #ifdef HAVE_restore_stack_nonlocal 1047 case SAVE_NONLOCAL: 1048 if (HAVE_restore_stack_nonlocal) 1049 fcn = gen_restore_stack_nonlocal; 1050 break; 1051 #endif 1052 default: 1053 break; 1054 } 1055 1056 if (sa != 0) 1057 { 1058 sa = validize_mem (sa); 1059 /* These clobbers prevent the scheduler from moving 1060 references to variable arrays below the code 1061 that deletes (pops) the arrays. */ 1062 emit_clobber (gen_rtx_MEM (BLKmode, gen_rtx_SCRATCH (VOIDmode))); 1063 emit_clobber (gen_rtx_MEM (BLKmode, stack_pointer_rtx)); 1064 } 1065 1066 discard_pending_stack_adjust (); 1067 1068 if (after) 1069 { 1070 rtx seq; 1071 1072 start_sequence (); 1073 emit_insn (fcn (stack_pointer_rtx, sa)); 1074 seq = get_insns (); 1075 end_sequence (); 1076 emit_insn_after (seq, after); 1077 } 1078 else 1079 emit_insn (fcn (stack_pointer_rtx, sa)); 1080 } 1081 1082 /* Invoke emit_stack_save on the nonlocal_goto_save_area for the current 1083 function. This function should be called whenever we allocate or 1084 deallocate dynamic stack space. */ 1085 1086 void 1087 update_nonlocal_goto_save_area (void) 1088 { 1089 tree t_save; 1090 rtx r_save; 1091 1092 /* The nonlocal_goto_save_area object is an array of N pointers. The 1093 first one is used for the frame pointer save; the rest are sized by 1094 STACK_SAVEAREA_MODE. Create a reference to array index 1, the first 1095 of the stack save area slots. */ 1096 t_save = build4 (ARRAY_REF, ptr_type_node, cfun->nonlocal_goto_save_area, 1097 integer_one_node, NULL_TREE, NULL_TREE); 1098 r_save = expand_expr (t_save, NULL_RTX, VOIDmode, EXPAND_WRITE); 1099 1100 emit_stack_save (SAVE_NONLOCAL, &r_save, NULL_RTX); 1101 } 1102 1103 /* Return an rtx representing the address of an area of memory dynamically 1104 pushed on the stack. This region of memory is always aligned to 1105 a multiple of BIGGEST_ALIGNMENT. 1106 1107 Any required stack pointer alignment is preserved. 1108 1109 SIZE is an rtx representing the size of the area. 1110 TARGET is a place in which the address can be placed. 1111 1112 KNOWN_ALIGN is the alignment (in bits) that we know SIZE has. */ 1113 1114 rtx 1115 allocate_dynamic_stack_space (rtx size, rtx target, int known_align) 1116 { 1117 /* If we're asking for zero bytes, it doesn't matter what we point 1118 to since we can't dereference it. But return a reasonable 1119 address anyway. */ 1120 if (size == const0_rtx) 1121 return virtual_stack_dynamic_rtx; 1122 1123 /* Otherwise, show we're calling alloca or equivalent. */ 1124 cfun->calls_alloca = 1; 1125 1126 /* Ensure the size is in the proper mode. */ 1127 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode) 1128 size = convert_to_mode (Pmode, size, 1); 1129 1130 /* We can't attempt to minimize alignment necessary, because we don't 1131 know the final value of preferred_stack_boundary yet while executing 1132 this code. */ 1133 crtl->preferred_stack_boundary = PREFERRED_STACK_BOUNDARY; 1134 1135 /* We will need to ensure that the address we return is aligned to 1136 BIGGEST_ALIGNMENT. If STACK_DYNAMIC_OFFSET is defined, we don't 1137 always know its final value at this point in the compilation (it 1138 might depend on the size of the outgoing parameter lists, for 1139 example), so we must align the value to be returned in that case. 1140 (Note that STACK_DYNAMIC_OFFSET will have a default nonzero value if 1141 STACK_POINTER_OFFSET or ACCUMULATE_OUTGOING_ARGS are defined). 1142 We must also do an alignment operation on the returned value if 1143 the stack pointer alignment is less strict that BIGGEST_ALIGNMENT. 1144 1145 If we have to align, we must leave space in SIZE for the hole 1146 that might result from the alignment operation. */ 1147 1148 #if defined (STACK_DYNAMIC_OFFSET) || defined (STACK_POINTER_OFFSET) 1149 #define MUST_ALIGN 1 1150 #else 1151 #define MUST_ALIGN (PREFERRED_STACK_BOUNDARY < BIGGEST_ALIGNMENT) 1152 #endif 1153 1154 if (MUST_ALIGN) 1155 size 1156 = force_operand (plus_constant (size, 1157 BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1), 1158 NULL_RTX); 1159 1160 #ifdef SETJMP_VIA_SAVE_AREA 1161 /* If setjmp restores regs from a save area in the stack frame, 1162 avoid clobbering the reg save area. Note that the offset of 1163 virtual_incoming_args_rtx includes the preallocated stack args space. 1164 It would be no problem to clobber that, but it's on the wrong side 1165 of the old save area. 1166 1167 What used to happen is that, since we did not know for sure 1168 whether setjmp() was invoked until after RTL generation, we 1169 would use reg notes to store the "optimized" size and fix things 1170 up later. These days we know this information before we ever 1171 start building RTL so the reg notes are unnecessary. */ 1172 if (!cfun->calls_setjmp) 1173 { 1174 int align = PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT; 1175 1176 /* ??? Code below assumes that the save area needs maximal 1177 alignment. This constraint may be too strong. */ 1178 gcc_assert (PREFERRED_STACK_BOUNDARY == BIGGEST_ALIGNMENT); 1179 1180 if (CONST_INT_P (size)) 1181 { 1182 HOST_WIDE_INT new_size = INTVAL (size) / align * align; 1183 1184 if (INTVAL (size) != new_size) 1185 size = GEN_INT (new_size); 1186 } 1187 else 1188 { 1189 /* Since we know overflow is not possible, we avoid using 1190 CEIL_DIV_EXPR and use TRUNC_DIV_EXPR instead. */ 1191 size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size, 1192 GEN_INT (align), NULL_RTX, 1); 1193 size = expand_mult (Pmode, size, 1194 GEN_INT (align), NULL_RTX, 1); 1195 } 1196 } 1197 else 1198 { 1199 rtx dynamic_offset 1200 = expand_binop (Pmode, sub_optab, virtual_stack_dynamic_rtx, 1201 stack_pointer_rtx, NULL_RTX, 1, OPTAB_LIB_WIDEN); 1202 1203 size = expand_binop (Pmode, add_optab, size, dynamic_offset, 1204 NULL_RTX, 1, OPTAB_LIB_WIDEN); 1205 } 1206 #endif /* SETJMP_VIA_SAVE_AREA */ 1207 1208 /* Round the size to a multiple of the required stack alignment. 1209 Since the stack if presumed to be rounded before this allocation, 1210 this will maintain the required alignment. 1211 1212 If the stack grows downward, we could save an insn by subtracting 1213 SIZE from the stack pointer and then aligning the stack pointer. 1214 The problem with this is that the stack pointer may be unaligned 1215 between the execution of the subtraction and alignment insns and 1216 some machines do not allow this. Even on those that do, some 1217 signal handlers malfunction if a signal should occur between those 1218 insns. Since this is an extremely rare event, we have no reliable 1219 way of knowing which systems have this problem. So we avoid even 1220 momentarily mis-aligning the stack. */ 1221 1222 /* If we added a variable amount to SIZE, 1223 we can no longer assume it is aligned. */ 1224 #if !defined (SETJMP_VIA_SAVE_AREA) 1225 if (MUST_ALIGN || known_align % PREFERRED_STACK_BOUNDARY != 0) 1226 #endif 1227 size = round_push (size); 1228 1229 do_pending_stack_adjust (); 1230 1231 /* We ought to be called always on the toplevel and stack ought to be aligned 1232 properly. */ 1233 gcc_assert (!(stack_pointer_delta 1234 % (PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT))); 1235 1236 /* If needed, check that we have the required amount of stack. Take into 1237 account what has already been checked. */ 1238 if (STACK_CHECK_MOVING_SP) 1239 ; 1240 else if (flag_stack_check == GENERIC_STACK_CHECK) 1241 probe_stack_range (STACK_OLD_CHECK_PROTECT + STACK_CHECK_MAX_FRAME_SIZE, 1242 size); 1243 else if (flag_stack_check == STATIC_BUILTIN_STACK_CHECK) 1244 probe_stack_range (STACK_CHECK_PROTECT, size); 1245 1246 /* Don't use a TARGET that isn't a pseudo or is the wrong mode. */ 1247 if (target == 0 || !REG_P (target) 1248 || REGNO (target) < FIRST_PSEUDO_REGISTER 1249 || GET_MODE (target) != Pmode) 1250 target = gen_reg_rtx (Pmode); 1251 1252 mark_reg_pointer (target, known_align); 1253 1254 /* Perform the required allocation from the stack. Some systems do 1255 this differently than simply incrementing/decrementing from the 1256 stack pointer, such as acquiring the space by calling malloc(). */ 1257 #ifdef HAVE_allocate_stack 1258 if (HAVE_allocate_stack) 1259 { 1260 enum machine_mode mode = STACK_SIZE_MODE; 1261 insn_operand_predicate_fn pred; 1262 1263 /* We don't have to check against the predicate for operand 0 since 1264 TARGET is known to be a pseudo of the proper mode, which must 1265 be valid for the operand. For operand 1, convert to the 1266 proper mode and validate. */ 1267 if (mode == VOIDmode) 1268 mode = insn_data[(int) CODE_FOR_allocate_stack].operand[1].mode; 1269 1270 pred = insn_data[(int) CODE_FOR_allocate_stack].operand[1].predicate; 1271 if (pred && ! ((*pred) (size, mode))) 1272 size = copy_to_mode_reg (mode, convert_to_mode (mode, size, 1)); 1273 1274 emit_insn (gen_allocate_stack (target, size)); 1275 } 1276 else 1277 #endif 1278 { 1279 #ifndef STACK_GROWS_DOWNWARD 1280 emit_move_insn (target, virtual_stack_dynamic_rtx); 1281 #endif 1282 1283 /* Check stack bounds if necessary. */ 1284 if (crtl->limit_stack) 1285 { 1286 rtx available; 1287 rtx space_available = gen_label_rtx (); 1288 #ifdef STACK_GROWS_DOWNWARD 1289 available = expand_binop (Pmode, sub_optab, 1290 stack_pointer_rtx, stack_limit_rtx, 1291 NULL_RTX, 1, OPTAB_WIDEN); 1292 #else 1293 available = expand_binop (Pmode, sub_optab, 1294 stack_limit_rtx, stack_pointer_rtx, 1295 NULL_RTX, 1, OPTAB_WIDEN); 1296 #endif 1297 emit_cmp_and_jump_insns (available, size, GEU, NULL_RTX, Pmode, 1, 1298 space_available); 1299 #ifdef HAVE_trap 1300 if (HAVE_trap) 1301 emit_insn (gen_trap ()); 1302 else 1303 #endif 1304 error ("stack limits not supported on this target"); 1305 emit_barrier (); 1306 emit_label (space_available); 1307 } 1308 1309 if (flag_stack_check && STACK_CHECK_MOVING_SP) 1310 anti_adjust_stack_and_probe (size, false); 1311 else 1312 anti_adjust_stack (size); 1313 1314 #ifdef STACK_GROWS_DOWNWARD 1315 emit_move_insn (target, virtual_stack_dynamic_rtx); 1316 #endif 1317 } 1318 1319 if (MUST_ALIGN) 1320 { 1321 /* CEIL_DIV_EXPR needs to worry about the addition overflowing, 1322 but we know it can't. So add ourselves and then do 1323 TRUNC_DIV_EXPR. */ 1324 target = expand_binop (Pmode, add_optab, target, 1325 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1), 1326 NULL_RTX, 1, OPTAB_LIB_WIDEN); 1327 target = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, target, 1328 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT), 1329 NULL_RTX, 1); 1330 target = expand_mult (Pmode, target, 1331 GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT), 1332 NULL_RTX, 1); 1333 } 1334 1335 /* Record the new stack level for nonlocal gotos. */ 1336 if (cfun->nonlocal_goto_save_area != 0) 1337 update_nonlocal_goto_save_area (); 1338 1339 return target; 1340 } 1341 1342 /* A front end may want to override GCC's stack checking by providing a 1343 run-time routine to call to check the stack, so provide a mechanism for 1344 calling that routine. */ 1345 1346 static GTY(()) rtx stack_check_libfunc; 1347 1348 void 1349 set_stack_check_libfunc (rtx libfunc) 1350 { 1351 stack_check_libfunc = libfunc; 1352 } 1353 1354 /* Emit one stack probe at ADDRESS, an address within the stack. */ 1355 1356 static void 1357 emit_stack_probe (rtx address) 1358 { 1359 rtx memref = gen_rtx_MEM (word_mode, address); 1360 1361 MEM_VOLATILE_P (memref) = 1; 1362 1363 /* See if we have an insn to probe the stack. */ 1364 #ifdef HAVE_probe_stack 1365 if (HAVE_probe_stack) 1366 emit_insn (gen_probe_stack (memref)); 1367 else 1368 #endif 1369 emit_move_insn (memref, const0_rtx); 1370 } 1371 1372 /* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive. 1373 FIRST is a constant and size is a Pmode RTX. These are offsets from 1374 the current stack pointer. STACK_GROWS_DOWNWARD says whether to add 1375 or subtract them from the stack pointer. */ 1376 1377 #define PROBE_INTERVAL (1 << STACK_CHECK_PROBE_INTERVAL_EXP) 1378 1379 #ifdef STACK_GROWS_DOWNWARD 1380 #define STACK_GROW_OP MINUS 1381 #define STACK_GROW_OPTAB sub_optab 1382 #define STACK_GROW_OFF(off) -(off) 1383 #else 1384 #define STACK_GROW_OP PLUS 1385 #define STACK_GROW_OPTAB add_optab 1386 #define STACK_GROW_OFF(off) (off) 1387 #endif 1388 1389 void 1390 probe_stack_range (HOST_WIDE_INT first, rtx size) 1391 { 1392 /* First ensure SIZE is Pmode. */ 1393 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode) 1394 size = convert_to_mode (Pmode, size, 1); 1395 1396 /* Next see if we have a function to check the stack. */ 1397 if (stack_check_libfunc) 1398 { 1399 rtx addr = memory_address (Pmode, 1400 gen_rtx_fmt_ee (STACK_GROW_OP, Pmode, 1401 stack_pointer_rtx, 1402 plus_constant (size, first))); 1403 emit_library_call (stack_check_libfunc, LCT_NORMAL, VOIDmode, 1, addr, 1404 Pmode); 1405 } 1406 1407 /* Next see if we have an insn to check the stack. */ 1408 #ifdef HAVE_check_stack 1409 else if (HAVE_check_stack) 1410 { 1411 rtx addr = memory_address (Pmode, 1412 gen_rtx_fmt_ee (STACK_GROW_OP, Pmode, 1413 stack_pointer_rtx, 1414 plus_constant (size, first))); 1415 insn_operand_predicate_fn pred 1416 = insn_data[(int) CODE_FOR_check_stack].operand[0].predicate; 1417 if (pred && !((*pred) (addr, Pmode))) 1418 addr = copy_to_mode_reg (Pmode, addr); 1419 1420 emit_insn (gen_check_stack (addr)); 1421 } 1422 #endif 1423 1424 /* Otherwise we have to generate explicit probes. If we have a constant 1425 small number of them to generate, that's the easy case. */ 1426 else if (CONST_INT_P (size) && INTVAL (size) < 7 * PROBE_INTERVAL) 1427 { 1428 HOST_WIDE_INT isize = INTVAL (size), i; 1429 rtx addr; 1430 1431 /* Probe at FIRST + N * PROBE_INTERVAL for values of N from 1 until 1432 it exceeds SIZE. If only one probe is needed, this will not 1433 generate any code. Then probe at FIRST + SIZE. */ 1434 for (i = PROBE_INTERVAL; i < isize; i += PROBE_INTERVAL) 1435 { 1436 addr = memory_address (Pmode, 1437 plus_constant (stack_pointer_rtx, 1438 STACK_GROW_OFF (first + i))); 1439 emit_stack_probe (addr); 1440 } 1441 1442 addr = memory_address (Pmode, 1443 plus_constant (stack_pointer_rtx, 1444 STACK_GROW_OFF (first + isize))); 1445 emit_stack_probe (addr); 1446 } 1447 1448 /* In the variable case, do the same as above, but in a loop. Note that we 1449 must be extra careful with variables wrapping around because we might be 1450 at the very top (or the very bottom) of the address space and we have to 1451 be able to handle this case properly; in particular, we use an equality 1452 test for the loop condition. */ 1453 else 1454 { 1455 rtx rounded_size, rounded_size_op, test_addr, last_addr, temp; 1456 rtx loop_lab = gen_label_rtx (); 1457 rtx end_lab = gen_label_rtx (); 1458 1459 1460 /* Step 1: round SIZE to the previous multiple of the interval. */ 1461 1462 /* ROUNDED_SIZE = SIZE & -PROBE_INTERVAL */ 1463 rounded_size 1464 = simplify_gen_binary (AND, Pmode, size, GEN_INT (-PROBE_INTERVAL)); 1465 rounded_size_op = force_operand (rounded_size, NULL_RTX); 1466 1467 1468 /* Step 2: compute initial and final value of the loop counter. */ 1469 1470 /* TEST_ADDR = SP + FIRST. */ 1471 test_addr = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode, 1472 stack_pointer_rtx, 1473 GEN_INT (first)), NULL_RTX); 1474 1475 /* LAST_ADDR = SP + FIRST + ROUNDED_SIZE. */ 1476 last_addr = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode, 1477 test_addr, 1478 rounded_size_op), NULL_RTX); 1479 1480 1481 /* Step 3: the loop 1482 1483 while (TEST_ADDR != LAST_ADDR) 1484 { 1485 TEST_ADDR = TEST_ADDR + PROBE_INTERVAL 1486 probe at TEST_ADDR 1487 } 1488 1489 probes at FIRST + N * PROBE_INTERVAL for values of N from 1 1490 until it is equal to ROUNDED_SIZE. */ 1491 1492 emit_label (loop_lab); 1493 1494 /* Jump to END_LAB if TEST_ADDR == LAST_ADDR. */ 1495 emit_cmp_and_jump_insns (test_addr, last_addr, EQ, NULL_RTX, Pmode, 1, 1496 end_lab); 1497 1498 /* TEST_ADDR = TEST_ADDR + PROBE_INTERVAL. */ 1499 temp = expand_binop (Pmode, STACK_GROW_OPTAB, test_addr, 1500 GEN_INT (PROBE_INTERVAL), test_addr, 1501 1, OPTAB_WIDEN); 1502 1503 gcc_assert (temp == test_addr); 1504 1505 /* Probe at TEST_ADDR. */ 1506 emit_stack_probe (test_addr); 1507 1508 emit_jump (loop_lab); 1509 1510 emit_label (end_lab); 1511 1512 1513 /* Step 4: probe at FIRST + SIZE if we cannot assert at compile-time 1514 that SIZE is equal to ROUNDED_SIZE. */ 1515 1516 /* TEMP = SIZE - ROUNDED_SIZE. */ 1517 temp = simplify_gen_binary (MINUS, Pmode, size, rounded_size); 1518 if (temp != const0_rtx) 1519 { 1520 rtx addr; 1521 1522 if (GET_CODE (temp) == CONST_INT) 1523 { 1524 /* Use [base + disp} addressing mode if supported. */ 1525 HOST_WIDE_INT offset = INTVAL (temp); 1526 addr = memory_address (Pmode, 1527 plus_constant (last_addr, 1528 STACK_GROW_OFF (offset))); 1529 } 1530 else 1531 { 1532 /* Manual CSE if the difference is not known at compile-time. */ 1533 temp = gen_rtx_MINUS (Pmode, size, rounded_size_op); 1534 addr = memory_address (Pmode, 1535 gen_rtx_fmt_ee (STACK_GROW_OP, Pmode, 1536 last_addr, temp)); 1537 } 1538 1539 emit_stack_probe (addr); 1540 } 1541 } 1542 } 1543 1544 /* Adjust the stack pointer by minus SIZE (an rtx for a number of bytes) 1545 while probing it. This pushes when SIZE is positive. SIZE need not 1546 be constant. If ADJUST_BACK is true, adjust back the stack pointer 1547 by plus SIZE at the end. */ 1548 1549 void 1550 anti_adjust_stack_and_probe (rtx size, bool adjust_back) 1551 { 1552 /* We skip the probe for the first interval + a small dope of 4 words and 1553 probe that many bytes past the specified size to maintain a protection 1554 area at the botton of the stack. */ 1555 const int dope = 4 * UNITS_PER_WORD; 1556 1557 /* First ensure SIZE is Pmode. */ 1558 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode) 1559 size = convert_to_mode (Pmode, size, 1); 1560 1561 /* If we have a constant small number of probes to generate, that's the 1562 easy case. */ 1563 if (GET_CODE (size) == CONST_INT && INTVAL (size) < 7 * PROBE_INTERVAL) 1564 { 1565 HOST_WIDE_INT isize = INTVAL (size), i; 1566 bool first_probe = true; 1567 1568 /* Adjust SP and probe to PROBE_INTERVAL + N * PROBE_INTERVAL for 1569 values of N from 1 until it exceeds SIZE. If only one probe is 1570 needed, this will not generate any code. Then adjust and probe 1571 to PROBE_INTERVAL + SIZE. */ 1572 for (i = PROBE_INTERVAL; i < isize; i += PROBE_INTERVAL) 1573 { 1574 if (first_probe) 1575 { 1576 anti_adjust_stack (GEN_INT (2 * PROBE_INTERVAL + dope)); 1577 first_probe = false; 1578 } 1579 else 1580 anti_adjust_stack (GEN_INT (PROBE_INTERVAL)); 1581 emit_stack_probe (stack_pointer_rtx); 1582 } 1583 1584 if (first_probe) 1585 anti_adjust_stack (plus_constant (size, PROBE_INTERVAL + dope)); 1586 else 1587 anti_adjust_stack (plus_constant (size, PROBE_INTERVAL - i)); 1588 emit_stack_probe (stack_pointer_rtx); 1589 } 1590 1591 /* In the variable case, do the same as above, but in a loop. Note that we 1592 must be extra careful with variables wrapping around because we might be 1593 at the very top (or the very bottom) of the address space and we have to 1594 be able to handle this case properly; in particular, we use an equality 1595 test for the loop condition. */ 1596 else 1597 { 1598 rtx rounded_size, rounded_size_op, last_addr, temp; 1599 rtx loop_lab = gen_label_rtx (); 1600 rtx end_lab = gen_label_rtx (); 1601 1602 1603 /* Step 1: round SIZE to the previous multiple of the interval. */ 1604 1605 /* ROUNDED_SIZE = SIZE & -PROBE_INTERVAL */ 1606 rounded_size 1607 = simplify_gen_binary (AND, Pmode, size, GEN_INT (-PROBE_INTERVAL)); 1608 rounded_size_op = force_operand (rounded_size, NULL_RTX); 1609 1610 1611 /* Step 2: compute initial and final value of the loop counter. */ 1612 1613 /* SP = SP_0 + PROBE_INTERVAL. */ 1614 anti_adjust_stack (GEN_INT (PROBE_INTERVAL + dope)); 1615 1616 /* LAST_ADDR = SP_0 + PROBE_INTERVAL + ROUNDED_SIZE. */ 1617 last_addr = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode, 1618 stack_pointer_rtx, 1619 rounded_size_op), NULL_RTX); 1620 1621 1622 /* Step 3: the loop 1623 1624 while (SP != LAST_ADDR) 1625 { 1626 SP = SP + PROBE_INTERVAL 1627 probe at SP 1628 } 1629 1630 adjusts SP and probes to PROBE_INTERVAL + N * PROBE_INTERVAL for 1631 values of N from 1 until it is equal to ROUNDED_SIZE. */ 1632 1633 emit_label (loop_lab); 1634 1635 /* Jump to END_LAB if SP == LAST_ADDR. */ 1636 emit_cmp_and_jump_insns (stack_pointer_rtx, last_addr, EQ, NULL_RTX, 1637 Pmode, 1, end_lab); 1638 1639 /* SP = SP + PROBE_INTERVAL and probe at SP. */ 1640 anti_adjust_stack (GEN_INT (PROBE_INTERVAL)); 1641 emit_stack_probe (stack_pointer_rtx); 1642 1643 emit_jump (loop_lab); 1644 1645 emit_label (end_lab); 1646 1647 1648 /* Step 4: adjust SP and probe to PROBE_INTERVAL + SIZE if we cannot 1649 assert at compile-time that SIZE is equal to ROUNDED_SIZE. */ 1650 1651 /* TEMP = SIZE - ROUNDED_SIZE. */ 1652 temp = simplify_gen_binary (MINUS, Pmode, size, rounded_size); 1653 if (temp != const0_rtx) 1654 { 1655 /* Manual CSE if the difference is not known at compile-time. */ 1656 if (GET_CODE (temp) != CONST_INT) 1657 temp = gen_rtx_MINUS (Pmode, size, rounded_size_op); 1658 anti_adjust_stack (temp); 1659 emit_stack_probe (stack_pointer_rtx); 1660 } 1661 } 1662 1663 /* Adjust back and account for the additional first interval. */ 1664 if (adjust_back) 1665 adjust_stack (plus_constant (size, PROBE_INTERVAL + dope)); 1666 else 1667 adjust_stack (GEN_INT (PROBE_INTERVAL + dope)); 1668 } 1669 1670 /* Return an rtx representing the register or memory location 1671 in which a scalar value of data type VALTYPE 1672 was returned by a function call to function FUNC. 1673 FUNC is a FUNCTION_DECL, FNTYPE a FUNCTION_TYPE node if the precise 1674 function is known, otherwise 0. 1675 OUTGOING is 1 if on a machine with register windows this function 1676 should return the register in which the function will put its result 1677 and 0 otherwise. */ 1678 1679 rtx 1680 hard_function_value (const_tree valtype, const_tree func, const_tree fntype, 1681 int outgoing ATTRIBUTE_UNUSED) 1682 { 1683 rtx val; 1684 1685 val = targetm.calls.function_value (valtype, func ? func : fntype, outgoing); 1686 1687 if (REG_P (val) 1688 && GET_MODE (val) == BLKmode) 1689 { 1690 unsigned HOST_WIDE_INT bytes = int_size_in_bytes (valtype); 1691 enum machine_mode tmpmode; 1692 1693 /* int_size_in_bytes can return -1. We don't need a check here 1694 since the value of bytes will then be large enough that no 1695 mode will match anyway. */ 1696 1697 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT); 1698 tmpmode != VOIDmode; 1699 tmpmode = GET_MODE_WIDER_MODE (tmpmode)) 1700 { 1701 /* Have we found a large enough mode? */ 1702 if (GET_MODE_SIZE (tmpmode) >= bytes) 1703 break; 1704 } 1705 1706 /* No suitable mode found. */ 1707 gcc_assert (tmpmode != VOIDmode); 1708 1709 PUT_MODE (val, tmpmode); 1710 } 1711 return val; 1712 } 1713 1714 /* Return an rtx representing the register or memory location 1715 in which a scalar value of mode MODE was returned by a library call. */ 1716 1717 rtx 1718 hard_libcall_value (enum machine_mode mode, rtx fun) 1719 { 1720 return targetm.calls.libcall_value (mode, fun); 1721 } 1722 1723 /* Look up the tree code for a given rtx code 1724 to provide the arithmetic operation for REAL_ARITHMETIC. 1725 The function returns an int because the caller may not know 1726 what `enum tree_code' means. */ 1727 1728 int 1729 rtx_to_tree_code (enum rtx_code code) 1730 { 1731 enum tree_code tcode; 1732 1733 switch (code) 1734 { 1735 case PLUS: 1736 tcode = PLUS_EXPR; 1737 break; 1738 case MINUS: 1739 tcode = MINUS_EXPR; 1740 break; 1741 case MULT: 1742 tcode = MULT_EXPR; 1743 break; 1744 case DIV: 1745 tcode = RDIV_EXPR; 1746 break; 1747 case SMIN: 1748 tcode = MIN_EXPR; 1749 break; 1750 case SMAX: 1751 tcode = MAX_EXPR; 1752 break; 1753 default: 1754 tcode = LAST_AND_UNUSED_TREE_CODE; 1755 break; 1756 } 1757 return ((int) tcode); 1758 } 1759 1760 #include "gt-explow.h" 1761