1 /* Subroutines for manipulating rtx's in semantically interesting ways. 2 Copyright (C) 1987-2013 Free Software Foundation, Inc. 3 4 This file is part of GCC. 5 6 GCC is free software; you can redistribute it and/or modify it under 7 the terms of the GNU General Public License as published by the Free 8 Software Foundation; either version 3, or (at your option) any later 9 version. 10 11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY 12 WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 for more details. 15 16 You should have received a copy of the GNU General Public License 17 along with GCC; see the file COPYING3. If not see 18 <http://www.gnu.org/licenses/>. */ 19 20 21 #include "config.h" 22 #include "system.h" 23 #include "coretypes.h" 24 #include "tm.h" 25 #include "diagnostic-core.h" 26 #include "rtl.h" 27 #include "tree.h" 28 #include "tm_p.h" 29 #include "flags.h" 30 #include "except.h" 31 #include "function.h" 32 #include "expr.h" 33 #include "optabs.h" 34 #include "libfuncs.h" 35 #include "hard-reg-set.h" 36 #include "insn-config.h" 37 #include "ggc.h" 38 #include "recog.h" 39 #include "langhooks.h" 40 #include "target.h" 41 #include "common/common-target.h" 42 #include "output.h" 43 44 static rtx break_out_memory_refs (rtx); 45 46 47 /* Truncate and perhaps sign-extend C as appropriate for MODE. */ 48 49 HOST_WIDE_INT 50 trunc_int_for_mode (HOST_WIDE_INT c, enum machine_mode mode) 51 { 52 int width = GET_MODE_PRECISION (mode); 53 54 /* You want to truncate to a _what_? */ 55 gcc_assert (SCALAR_INT_MODE_P (mode)); 56 57 /* Canonicalize BImode to 0 and STORE_FLAG_VALUE. */ 58 if (mode == BImode) 59 return c & 1 ? STORE_FLAG_VALUE : 0; 60 61 /* Sign-extend for the requested mode. */ 62 63 if (width < HOST_BITS_PER_WIDE_INT) 64 { 65 HOST_WIDE_INT sign = 1; 66 sign <<= width - 1; 67 c &= (sign << 1) - 1; 68 c ^= sign; 69 c -= sign; 70 } 71 72 return c; 73 } 74 75 /* Return an rtx for the sum of X and the integer C, given that X has 76 mode MODE. */ 77 78 rtx 79 plus_constant (enum machine_mode mode, rtx x, HOST_WIDE_INT c) 80 { 81 RTX_CODE code; 82 rtx y; 83 rtx tem; 84 int all_constant = 0; 85 86 gcc_assert (GET_MODE (x) == VOIDmode || GET_MODE (x) == mode); 87 88 if (c == 0) 89 return x; 90 91 restart: 92 93 code = GET_CODE (x); 94 y = x; 95 96 switch (code) 97 { 98 case CONST_INT: 99 if (GET_MODE_BITSIZE (mode) > HOST_BITS_PER_WIDE_INT) 100 { 101 double_int di_x = double_int::from_shwi (INTVAL (x)); 102 double_int di_c = double_int::from_shwi (c); 103 104 bool overflow; 105 double_int v = di_x.add_with_sign (di_c, false, &overflow); 106 if (overflow) 107 gcc_unreachable (); 108 109 return immed_double_int_const (v, mode); 110 } 111 112 return gen_int_mode (INTVAL (x) + c, mode); 113 114 case CONST_DOUBLE: 115 { 116 double_int di_x = double_int::from_pair (CONST_DOUBLE_HIGH (x), 117 CONST_DOUBLE_LOW (x)); 118 double_int di_c = double_int::from_shwi (c); 119 120 bool overflow; 121 double_int v = di_x.add_with_sign (di_c, false, &overflow); 122 if (overflow) 123 /* Sorry, we have no way to represent overflows this wide. 124 To fix, add constant support wider than CONST_DOUBLE. */ 125 gcc_assert (GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_DOUBLE_INT); 126 127 return immed_double_int_const (v, mode); 128 } 129 130 case MEM: 131 /* If this is a reference to the constant pool, try replacing it with 132 a reference to a new constant. If the resulting address isn't 133 valid, don't return it because we have no way to validize it. */ 134 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF 135 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0))) 136 { 137 tem = plus_constant (mode, get_pool_constant (XEXP (x, 0)), c); 138 tem = force_const_mem (GET_MODE (x), tem); 139 if (memory_address_p (GET_MODE (tem), XEXP (tem, 0))) 140 return tem; 141 } 142 break; 143 144 case CONST: 145 /* If adding to something entirely constant, set a flag 146 so that we can add a CONST around the result. */ 147 x = XEXP (x, 0); 148 all_constant = 1; 149 goto restart; 150 151 case SYMBOL_REF: 152 case LABEL_REF: 153 all_constant = 1; 154 break; 155 156 case PLUS: 157 /* The interesting case is adding the integer to a sum. Look 158 for constant term in the sum and combine with C. For an 159 integer constant term or a constant term that is not an 160 explicit integer, we combine or group them together anyway. 161 162 We may not immediately return from the recursive call here, lest 163 all_constant gets lost. */ 164 165 if (CONSTANT_P (XEXP (x, 1))) 166 { 167 x = gen_rtx_PLUS (mode, XEXP (x, 0), 168 plus_constant (mode, 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 (mode, *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_SCALAR_INT: 346 if (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (from_mode)) 347 code = TRUNCATE; 348 else if (POINTERS_EXTEND_UNSIGNED < 0) 349 break; 350 else if (POINTERS_EXTEND_UNSIGNED > 0) 351 code = ZERO_EXTEND; 352 else 353 code = SIGN_EXTEND; 354 temp = simplify_unary_operation (code, to_mode, x, from_mode); 355 if (temp) 356 return temp; 357 break; 358 359 case SUBREG: 360 if ((SUBREG_PROMOTED_VAR_P (x) || REG_POINTER (SUBREG_REG (x))) 361 && GET_MODE (SUBREG_REG (x)) == to_mode) 362 return SUBREG_REG (x); 363 break; 364 365 case LABEL_REF: 366 temp = gen_rtx_LABEL_REF (to_mode, XEXP (x, 0)); 367 LABEL_REF_NONLOCAL_P (temp) = LABEL_REF_NONLOCAL_P (x); 368 return temp; 369 break; 370 371 case SYMBOL_REF: 372 temp = shallow_copy_rtx (x); 373 PUT_MODE (temp, to_mode); 374 return temp; 375 break; 376 377 case CONST: 378 return gen_rtx_CONST (to_mode, 379 convert_memory_address_addr_space 380 (to_mode, XEXP (x, 0), as)); 381 break; 382 383 case PLUS: 384 case MULT: 385 /* FIXME: For addition, we used to permute the conversion and 386 addition operation only if one operand is a constant and 387 converting the constant does not change it or if one operand 388 is a constant and we are using a ptr_extend instruction 389 (POINTERS_EXTEND_UNSIGNED < 0) even if the resulting address 390 may overflow/underflow. We relax the condition to include 391 zero-extend (POINTERS_EXTEND_UNSIGNED > 0) since the other 392 parts of the compiler depend on it. See PR 49721. 393 394 We can always safely permute them if we are making the address 395 narrower. */ 396 if (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (from_mode) 397 || (GET_CODE (x) == PLUS 398 && CONST_INT_P (XEXP (x, 1)) 399 && (POINTERS_EXTEND_UNSIGNED != 0 400 || XEXP (x, 1) == convert_memory_address_addr_space 401 (to_mode, XEXP (x, 1), as)))) 402 return gen_rtx_fmt_ee (GET_CODE (x), to_mode, 403 convert_memory_address_addr_space 404 (to_mode, XEXP (x, 0), as), 405 XEXP (x, 1)); 406 break; 407 408 default: 409 break; 410 } 411 412 return convert_modes (to_mode, from_mode, 413 x, POINTERS_EXTEND_UNSIGNED); 414 #endif /* defined(POINTERS_EXTEND_UNSIGNED) */ 415 } 416 417 /* Return something equivalent to X but valid as a memory address for something 418 of mode MODE in the named address space AS. When X is not itself valid, 419 this works by copying X or subexpressions of it into registers. */ 420 421 rtx 422 memory_address_addr_space (enum machine_mode mode, rtx x, addr_space_t as) 423 { 424 rtx oldx = x; 425 enum machine_mode address_mode = targetm.addr_space.address_mode (as); 426 427 x = convert_memory_address_addr_space (address_mode, x, as); 428 429 /* By passing constant addresses through registers 430 we get a chance to cse them. */ 431 if (! cse_not_expected && CONSTANT_P (x) && CONSTANT_ADDRESS_P (x)) 432 x = force_reg (address_mode, x); 433 434 /* We get better cse by rejecting indirect addressing at this stage. 435 Let the combiner create indirect addresses where appropriate. 436 For now, generate the code so that the subexpressions useful to share 437 are visible. But not if cse won't be done! */ 438 else 439 { 440 if (! cse_not_expected && !REG_P (x)) 441 x = break_out_memory_refs (x); 442 443 /* At this point, any valid address is accepted. */ 444 if (memory_address_addr_space_p (mode, x, as)) 445 goto done; 446 447 /* If it was valid before but breaking out memory refs invalidated it, 448 use it the old way. */ 449 if (memory_address_addr_space_p (mode, oldx, as)) 450 { 451 x = oldx; 452 goto done; 453 } 454 455 /* Perform machine-dependent transformations on X 456 in certain cases. This is not necessary since the code 457 below can handle all possible cases, but machine-dependent 458 transformations can make better code. */ 459 { 460 rtx orig_x = x; 461 x = targetm.addr_space.legitimize_address (x, oldx, mode, as); 462 if (orig_x != x && memory_address_addr_space_p (mode, x, as)) 463 goto done; 464 } 465 466 /* PLUS and MULT can appear in special ways 467 as the result of attempts to make an address usable for indexing. 468 Usually they are dealt with by calling force_operand, below. 469 But a sum containing constant terms is special 470 if removing them makes the sum a valid address: 471 then we generate that address in a register 472 and index off of it. We do this because it often makes 473 shorter code, and because the addresses thus generated 474 in registers often become common subexpressions. */ 475 if (GET_CODE (x) == PLUS) 476 { 477 rtx constant_term = const0_rtx; 478 rtx y = eliminate_constant_term (x, &constant_term); 479 if (constant_term == const0_rtx 480 || ! memory_address_addr_space_p (mode, y, as)) 481 x = force_operand (x, NULL_RTX); 482 else 483 { 484 y = gen_rtx_PLUS (GET_MODE (x), copy_to_reg (y), constant_term); 485 if (! memory_address_addr_space_p (mode, y, as)) 486 x = force_operand (x, NULL_RTX); 487 else 488 x = y; 489 } 490 } 491 492 else if (GET_CODE (x) == MULT || GET_CODE (x) == MINUS) 493 x = force_operand (x, NULL_RTX); 494 495 /* If we have a register that's an invalid address, 496 it must be a hard reg of the wrong class. Copy it to a pseudo. */ 497 else if (REG_P (x)) 498 x = copy_to_reg (x); 499 500 /* Last resort: copy the value to a register, since 501 the register is a valid address. */ 502 else 503 x = force_reg (address_mode, x); 504 } 505 506 done: 507 508 gcc_assert (memory_address_addr_space_p (mode, x, as)); 509 /* If we didn't change the address, we are done. Otherwise, mark 510 a reg as a pointer if we have REG or REG + CONST_INT. */ 511 if (oldx == x) 512 return x; 513 else if (REG_P (x)) 514 mark_reg_pointer (x, BITS_PER_UNIT); 515 else if (GET_CODE (x) == PLUS 516 && REG_P (XEXP (x, 0)) 517 && CONST_INT_P (XEXP (x, 1))) 518 mark_reg_pointer (XEXP (x, 0), BITS_PER_UNIT); 519 520 /* OLDX may have been the address on a temporary. Update the address 521 to indicate that X is now used. */ 522 update_temp_slot_address (oldx, x); 523 524 return x; 525 } 526 527 /* Convert a mem ref into one with a valid memory address. 528 Pass through anything else unchanged. */ 529 530 rtx 531 validize_mem (rtx ref) 532 { 533 if (!MEM_P (ref)) 534 return ref; 535 ref = use_anchored_address (ref); 536 if (memory_address_addr_space_p (GET_MODE (ref), XEXP (ref, 0), 537 MEM_ADDR_SPACE (ref))) 538 return ref; 539 540 /* Don't alter REF itself, since that is probably a stack slot. */ 541 return replace_equiv_address (ref, XEXP (ref, 0)); 542 } 543 544 /* If X is a memory reference to a member of an object block, try rewriting 545 it to use an anchor instead. Return the new memory reference on success 546 and the old one on failure. */ 547 548 rtx 549 use_anchored_address (rtx x) 550 { 551 rtx base; 552 HOST_WIDE_INT offset; 553 enum machine_mode mode; 554 555 if (!flag_section_anchors) 556 return x; 557 558 if (!MEM_P (x)) 559 return x; 560 561 /* Split the address into a base and offset. */ 562 base = XEXP (x, 0); 563 offset = 0; 564 if (GET_CODE (base) == CONST 565 && GET_CODE (XEXP (base, 0)) == PLUS 566 && CONST_INT_P (XEXP (XEXP (base, 0), 1))) 567 { 568 offset += INTVAL (XEXP (XEXP (base, 0), 1)); 569 base = XEXP (XEXP (base, 0), 0); 570 } 571 572 /* Check whether BASE is suitable for anchors. */ 573 if (GET_CODE (base) != SYMBOL_REF 574 || !SYMBOL_REF_HAS_BLOCK_INFO_P (base) 575 || SYMBOL_REF_ANCHOR_P (base) 576 || SYMBOL_REF_BLOCK (base) == NULL 577 || !targetm.use_anchors_for_symbol_p (base)) 578 return x; 579 580 /* Decide where BASE is going to be. */ 581 place_block_symbol (base); 582 583 /* Get the anchor we need to use. */ 584 offset += SYMBOL_REF_BLOCK_OFFSET (base); 585 base = get_section_anchor (SYMBOL_REF_BLOCK (base), offset, 586 SYMBOL_REF_TLS_MODEL (base)); 587 588 /* Work out the offset from the anchor. */ 589 offset -= SYMBOL_REF_BLOCK_OFFSET (base); 590 591 /* If we're going to run a CSE pass, force the anchor into a register. 592 We will then be able to reuse registers for several accesses, if the 593 target costs say that that's worthwhile. */ 594 mode = GET_MODE (base); 595 if (!cse_not_expected) 596 base = force_reg (mode, base); 597 598 return replace_equiv_address (x, plus_constant (mode, base, offset)); 599 } 600 601 /* Copy the value or contents of X to a new temp reg and return that reg. */ 602 603 rtx 604 copy_to_reg (rtx x) 605 { 606 rtx temp = gen_reg_rtx (GET_MODE (x)); 607 608 /* If not an operand, must be an address with PLUS and MULT so 609 do the computation. */ 610 if (! general_operand (x, VOIDmode)) 611 x = force_operand (x, temp); 612 613 if (x != temp) 614 emit_move_insn (temp, x); 615 616 return temp; 617 } 618 619 /* Like copy_to_reg but always give the new register mode Pmode 620 in case X is a constant. */ 621 622 rtx 623 copy_addr_to_reg (rtx x) 624 { 625 return copy_to_mode_reg (Pmode, x); 626 } 627 628 /* Like copy_to_reg but always give the new register mode MODE 629 in case X is a constant. */ 630 631 rtx 632 copy_to_mode_reg (enum machine_mode mode, rtx x) 633 { 634 rtx temp = gen_reg_rtx (mode); 635 636 /* If not an operand, must be an address with PLUS and MULT so 637 do the computation. */ 638 if (! general_operand (x, VOIDmode)) 639 x = force_operand (x, temp); 640 641 gcc_assert (GET_MODE (x) == mode || GET_MODE (x) == VOIDmode); 642 if (x != temp) 643 emit_move_insn (temp, x); 644 return temp; 645 } 646 647 /* Load X into a register if it is not already one. 648 Use mode MODE for the register. 649 X should be valid for mode MODE, but it may be a constant which 650 is valid for all integer modes; that's why caller must specify MODE. 651 652 The caller must not alter the value in the register we return, 653 since we mark it as a "constant" register. */ 654 655 rtx 656 force_reg (enum machine_mode mode, rtx x) 657 { 658 rtx temp, insn, set; 659 660 if (REG_P (x)) 661 return x; 662 663 if (general_operand (x, mode)) 664 { 665 temp = gen_reg_rtx (mode); 666 insn = emit_move_insn (temp, x); 667 } 668 else 669 { 670 temp = force_operand (x, NULL_RTX); 671 if (REG_P (temp)) 672 insn = get_last_insn (); 673 else 674 { 675 rtx temp2 = gen_reg_rtx (mode); 676 insn = emit_move_insn (temp2, temp); 677 temp = temp2; 678 } 679 } 680 681 /* Let optimizers know that TEMP's value never changes 682 and that X can be substituted for it. Don't get confused 683 if INSN set something else (such as a SUBREG of TEMP). */ 684 if (CONSTANT_P (x) 685 && (set = single_set (insn)) != 0 686 && SET_DEST (set) == temp 687 && ! rtx_equal_p (x, SET_SRC (set))) 688 set_unique_reg_note (insn, REG_EQUAL, x); 689 690 /* Let optimizers know that TEMP is a pointer, and if so, the 691 known alignment of that pointer. */ 692 { 693 unsigned align = 0; 694 if (GET_CODE (x) == SYMBOL_REF) 695 { 696 align = BITS_PER_UNIT; 697 if (SYMBOL_REF_DECL (x) && DECL_P (SYMBOL_REF_DECL (x))) 698 align = DECL_ALIGN (SYMBOL_REF_DECL (x)); 699 } 700 else if (GET_CODE (x) == LABEL_REF) 701 align = BITS_PER_UNIT; 702 else if (GET_CODE (x) == CONST 703 && GET_CODE (XEXP (x, 0)) == PLUS 704 && GET_CODE (XEXP (XEXP (x, 0), 0)) == SYMBOL_REF 705 && CONST_INT_P (XEXP (XEXP (x, 0), 1))) 706 { 707 rtx s = XEXP (XEXP (x, 0), 0); 708 rtx c = XEXP (XEXP (x, 0), 1); 709 unsigned sa, ca; 710 711 sa = BITS_PER_UNIT; 712 if (SYMBOL_REF_DECL (s) && DECL_P (SYMBOL_REF_DECL (s))) 713 sa = DECL_ALIGN (SYMBOL_REF_DECL (s)); 714 715 if (INTVAL (c) == 0) 716 align = sa; 717 else 718 { 719 ca = ctz_hwi (INTVAL (c)) * BITS_PER_UNIT; 720 align = MIN (sa, ca); 721 } 722 } 723 724 if (align || (MEM_P (x) && MEM_POINTER (x))) 725 mark_reg_pointer (temp, align); 726 } 727 728 return temp; 729 } 730 731 /* If X is a memory ref, copy its contents to a new temp reg and return 732 that reg. Otherwise, return X. */ 733 734 rtx 735 force_not_mem (rtx x) 736 { 737 rtx temp; 738 739 if (!MEM_P (x) || GET_MODE (x) == BLKmode) 740 return x; 741 742 temp = gen_reg_rtx (GET_MODE (x)); 743 744 if (MEM_POINTER (x)) 745 REG_POINTER (temp) = 1; 746 747 emit_move_insn (temp, x); 748 return temp; 749 } 750 751 /* Copy X to TARGET (if it's nonzero and a reg) 752 or to a new temp reg and return that reg. 753 MODE is the mode to use for X in case it is a constant. */ 754 755 rtx 756 copy_to_suggested_reg (rtx x, rtx target, enum machine_mode mode) 757 { 758 rtx temp; 759 760 if (target && REG_P (target)) 761 temp = target; 762 else 763 temp = gen_reg_rtx (mode); 764 765 emit_move_insn (temp, x); 766 return temp; 767 } 768 769 /* Return the mode to use to pass or return a scalar of TYPE and MODE. 770 PUNSIGNEDP points to the signedness of the type and may be adjusted 771 to show what signedness to use on extension operations. 772 773 FOR_RETURN is nonzero if the caller is promoting the return value 774 of FNDECL, else it is for promoting args. */ 775 776 enum machine_mode 777 promote_function_mode (const_tree type, enum machine_mode mode, int *punsignedp, 778 const_tree funtype, int for_return) 779 { 780 /* Called without a type node for a libcall. */ 781 if (type == NULL_TREE) 782 { 783 if (INTEGRAL_MODE_P (mode)) 784 return targetm.calls.promote_function_mode (NULL_TREE, mode, 785 punsignedp, funtype, 786 for_return); 787 else 788 return mode; 789 } 790 791 switch (TREE_CODE (type)) 792 { 793 case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE: 794 case REAL_TYPE: case OFFSET_TYPE: case FIXED_POINT_TYPE: 795 case POINTER_TYPE: case REFERENCE_TYPE: 796 return targetm.calls.promote_function_mode (type, mode, punsignedp, funtype, 797 for_return); 798 799 default: 800 return mode; 801 } 802 } 803 /* Return the mode to use to store a scalar of TYPE and MODE. 804 PUNSIGNEDP points to the signedness of the type and may be adjusted 805 to show what signedness to use on extension operations. */ 806 807 enum machine_mode 808 promote_mode (const_tree type ATTRIBUTE_UNUSED, enum machine_mode mode, 809 int *punsignedp ATTRIBUTE_UNUSED) 810 { 811 #ifdef PROMOTE_MODE 812 enum tree_code code; 813 int unsignedp; 814 #endif 815 816 /* For libcalls this is invoked without TYPE from the backends 817 TARGET_PROMOTE_FUNCTION_MODE hooks. Don't do anything in that 818 case. */ 819 if (type == NULL_TREE) 820 return mode; 821 822 /* FIXME: this is the same logic that was there until GCC 4.4, but we 823 probably want to test POINTERS_EXTEND_UNSIGNED even if PROMOTE_MODE 824 is not defined. The affected targets are M32C, S390, SPARC. */ 825 #ifdef PROMOTE_MODE 826 code = TREE_CODE (type); 827 unsignedp = *punsignedp; 828 829 switch (code) 830 { 831 case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE: 832 case REAL_TYPE: case OFFSET_TYPE: case FIXED_POINT_TYPE: 833 PROMOTE_MODE (mode, unsignedp, type); 834 *punsignedp = unsignedp; 835 return mode; 836 break; 837 838 #ifdef POINTERS_EXTEND_UNSIGNED 839 case REFERENCE_TYPE: 840 case POINTER_TYPE: 841 *punsignedp = POINTERS_EXTEND_UNSIGNED; 842 return targetm.addr_space.address_mode 843 (TYPE_ADDR_SPACE (TREE_TYPE (type))); 844 break; 845 #endif 846 847 default: 848 return mode; 849 } 850 #else 851 return mode; 852 #endif 853 } 854 855 856 /* Use one of promote_mode or promote_function_mode to find the promoted 857 mode of DECL. If PUNSIGNEDP is not NULL, store there the unsignedness 858 of DECL after promotion. */ 859 860 enum machine_mode 861 promote_decl_mode (const_tree decl, int *punsignedp) 862 { 863 tree type = TREE_TYPE (decl); 864 int unsignedp = TYPE_UNSIGNED (type); 865 enum machine_mode mode = DECL_MODE (decl); 866 enum machine_mode pmode; 867 868 if (TREE_CODE (decl) == RESULT_DECL 869 || TREE_CODE (decl) == PARM_DECL) 870 pmode = promote_function_mode (type, mode, &unsignedp, 871 TREE_TYPE (current_function_decl), 2); 872 else 873 pmode = promote_mode (type, mode, &unsignedp); 874 875 if (punsignedp) 876 *punsignedp = unsignedp; 877 return pmode; 878 } 879 880 881 /* Controls the behaviour of {anti_,}adjust_stack. */ 882 static bool suppress_reg_args_size; 883 884 /* A helper for adjust_stack and anti_adjust_stack. */ 885 886 static void 887 adjust_stack_1 (rtx adjust, bool anti_p) 888 { 889 rtx temp, insn; 890 891 #ifndef STACK_GROWS_DOWNWARD 892 /* Hereafter anti_p means subtract_p. */ 893 anti_p = !anti_p; 894 #endif 895 896 temp = expand_binop (Pmode, 897 anti_p ? sub_optab : add_optab, 898 stack_pointer_rtx, adjust, stack_pointer_rtx, 0, 899 OPTAB_LIB_WIDEN); 900 901 if (temp != stack_pointer_rtx) 902 insn = emit_move_insn (stack_pointer_rtx, temp); 903 else 904 { 905 insn = get_last_insn (); 906 temp = single_set (insn); 907 gcc_assert (temp != NULL && SET_DEST (temp) == stack_pointer_rtx); 908 } 909 910 if (!suppress_reg_args_size) 911 add_reg_note (insn, REG_ARGS_SIZE, GEN_INT (stack_pointer_delta)); 912 } 913 914 /* Adjust the stack pointer by ADJUST (an rtx for a number of bytes). 915 This pops when ADJUST is positive. ADJUST need not be constant. */ 916 917 void 918 adjust_stack (rtx adjust) 919 { 920 if (adjust == const0_rtx) 921 return; 922 923 /* We expect all variable sized adjustments to be multiple of 924 PREFERRED_STACK_BOUNDARY. */ 925 if (CONST_INT_P (adjust)) 926 stack_pointer_delta -= INTVAL (adjust); 927 928 adjust_stack_1 (adjust, false); 929 } 930 931 /* Adjust the stack pointer by minus ADJUST (an rtx for a number of bytes). 932 This pushes when ADJUST is positive. ADJUST need not be constant. */ 933 934 void 935 anti_adjust_stack (rtx adjust) 936 { 937 if (adjust == const0_rtx) 938 return; 939 940 /* We expect all variable sized adjustments to be multiple of 941 PREFERRED_STACK_BOUNDARY. */ 942 if (CONST_INT_P (adjust)) 943 stack_pointer_delta += INTVAL (adjust); 944 945 adjust_stack_1 (adjust, true); 946 } 947 948 /* Round the size of a block to be pushed up to the boundary required 949 by this machine. SIZE is the desired size, which need not be constant. */ 950 951 static rtx 952 round_push (rtx size) 953 { 954 rtx align_rtx, alignm1_rtx; 955 956 if (!SUPPORTS_STACK_ALIGNMENT 957 || crtl->preferred_stack_boundary == MAX_SUPPORTED_STACK_ALIGNMENT) 958 { 959 int align = crtl->preferred_stack_boundary / BITS_PER_UNIT; 960 961 if (align == 1) 962 return size; 963 964 if (CONST_INT_P (size)) 965 { 966 HOST_WIDE_INT new_size = (INTVAL (size) + align - 1) / align * align; 967 968 if (INTVAL (size) != new_size) 969 size = GEN_INT (new_size); 970 return size; 971 } 972 973 align_rtx = GEN_INT (align); 974 alignm1_rtx = GEN_INT (align - 1); 975 } 976 else 977 { 978 /* If crtl->preferred_stack_boundary might still grow, use 979 virtual_preferred_stack_boundary_rtx instead. This will be 980 substituted by the right value in vregs pass and optimized 981 during combine. */ 982 align_rtx = virtual_preferred_stack_boundary_rtx; 983 alignm1_rtx = force_operand (plus_constant (Pmode, align_rtx, -1), 984 NULL_RTX); 985 } 986 987 /* CEIL_DIV_EXPR needs to worry about the addition overflowing, 988 but we know it can't. So add ourselves and then do 989 TRUNC_DIV_EXPR. */ 990 size = expand_binop (Pmode, add_optab, size, alignm1_rtx, 991 NULL_RTX, 1, OPTAB_LIB_WIDEN); 992 size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size, align_rtx, 993 NULL_RTX, 1); 994 size = expand_mult (Pmode, size, align_rtx, NULL_RTX, 1); 995 996 return size; 997 } 998 999 /* Save the stack pointer for the purpose in SAVE_LEVEL. PSAVE is a pointer 1000 to a previously-created save area. If no save area has been allocated, 1001 this function will allocate one. If a save area is specified, it 1002 must be of the proper mode. */ 1003 1004 void 1005 emit_stack_save (enum save_level save_level, rtx *psave) 1006 { 1007 rtx sa = *psave; 1008 /* The default is that we use a move insn and save in a Pmode object. */ 1009 rtx (*fcn) (rtx, rtx) = gen_move_insn; 1010 enum machine_mode mode = STACK_SAVEAREA_MODE (save_level); 1011 1012 /* See if this machine has anything special to do for this kind of save. */ 1013 switch (save_level) 1014 { 1015 #ifdef HAVE_save_stack_block 1016 case SAVE_BLOCK: 1017 if (HAVE_save_stack_block) 1018 fcn = gen_save_stack_block; 1019 break; 1020 #endif 1021 #ifdef HAVE_save_stack_function 1022 case SAVE_FUNCTION: 1023 if (HAVE_save_stack_function) 1024 fcn = gen_save_stack_function; 1025 break; 1026 #endif 1027 #ifdef HAVE_save_stack_nonlocal 1028 case SAVE_NONLOCAL: 1029 if (HAVE_save_stack_nonlocal) 1030 fcn = gen_save_stack_nonlocal; 1031 break; 1032 #endif 1033 default: 1034 break; 1035 } 1036 1037 /* If there is no save area and we have to allocate one, do so. Otherwise 1038 verify the save area is the proper mode. */ 1039 1040 if (sa == 0) 1041 { 1042 if (mode != VOIDmode) 1043 { 1044 if (save_level == SAVE_NONLOCAL) 1045 *psave = sa = assign_stack_local (mode, GET_MODE_SIZE (mode), 0); 1046 else 1047 *psave = sa = gen_reg_rtx (mode); 1048 } 1049 } 1050 1051 do_pending_stack_adjust (); 1052 if (sa != 0) 1053 sa = validize_mem (sa); 1054 emit_insn (fcn (sa, stack_pointer_rtx)); 1055 } 1056 1057 /* Restore the stack pointer for the purpose in SAVE_LEVEL. SA is the save 1058 area made by emit_stack_save. If it is zero, we have nothing to do. */ 1059 1060 void 1061 emit_stack_restore (enum save_level save_level, rtx sa) 1062 { 1063 /* The default is that we use a move insn. */ 1064 rtx (*fcn) (rtx, rtx) = gen_move_insn; 1065 1066 /* If stack_realign_drap, the x86 backend emits a prologue that aligns both 1067 STACK_POINTER and HARD_FRAME_POINTER. 1068 If stack_realign_fp, the x86 backend emits a prologue that aligns only 1069 STACK_POINTER. This renders the HARD_FRAME_POINTER unusable for accessing 1070 aligned variables, which is reflected in ix86_can_eliminate. 1071 We normally still have the realigned STACK_POINTER that we can use. 1072 But if there is a stack restore still present at reload, it can trigger 1073 mark_not_eliminable for the STACK_POINTER, leaving no way to eliminate 1074 FRAME_POINTER into a hard reg. 1075 To prevent this situation, we force need_drap if we emit a stack 1076 restore. */ 1077 if (SUPPORTS_STACK_ALIGNMENT) 1078 crtl->need_drap = true; 1079 1080 /* See if this machine has anything special to do for this kind of save. */ 1081 switch (save_level) 1082 { 1083 #ifdef HAVE_restore_stack_block 1084 case SAVE_BLOCK: 1085 if (HAVE_restore_stack_block) 1086 fcn = gen_restore_stack_block; 1087 break; 1088 #endif 1089 #ifdef HAVE_restore_stack_function 1090 case SAVE_FUNCTION: 1091 if (HAVE_restore_stack_function) 1092 fcn = gen_restore_stack_function; 1093 break; 1094 #endif 1095 #ifdef HAVE_restore_stack_nonlocal 1096 case SAVE_NONLOCAL: 1097 if (HAVE_restore_stack_nonlocal) 1098 fcn = gen_restore_stack_nonlocal; 1099 break; 1100 #endif 1101 default: 1102 break; 1103 } 1104 1105 if (sa != 0) 1106 { 1107 sa = validize_mem (sa); 1108 /* These clobbers prevent the scheduler from moving 1109 references to variable arrays below the code 1110 that deletes (pops) the arrays. */ 1111 emit_clobber (gen_rtx_MEM (BLKmode, gen_rtx_SCRATCH (VOIDmode))); 1112 emit_clobber (gen_rtx_MEM (BLKmode, stack_pointer_rtx)); 1113 } 1114 1115 discard_pending_stack_adjust (); 1116 1117 emit_insn (fcn (stack_pointer_rtx, sa)); 1118 } 1119 1120 /* Invoke emit_stack_save on the nonlocal_goto_save_area for the current 1121 function. This function should be called whenever we allocate or 1122 deallocate dynamic stack space. */ 1123 1124 void 1125 update_nonlocal_goto_save_area (void) 1126 { 1127 tree t_save; 1128 rtx r_save; 1129 1130 /* The nonlocal_goto_save_area object is an array of N pointers. The 1131 first one is used for the frame pointer save; the rest are sized by 1132 STACK_SAVEAREA_MODE. Create a reference to array index 1, the first 1133 of the stack save area slots. */ 1134 t_save = build4 (ARRAY_REF, 1135 TREE_TYPE (TREE_TYPE (cfun->nonlocal_goto_save_area)), 1136 cfun->nonlocal_goto_save_area, 1137 integer_one_node, NULL_TREE, NULL_TREE); 1138 r_save = expand_expr (t_save, NULL_RTX, VOIDmode, EXPAND_WRITE); 1139 1140 emit_stack_save (SAVE_NONLOCAL, &r_save); 1141 } 1142 1143 /* Return an rtx representing the address of an area of memory dynamically 1144 pushed on the stack. 1145 1146 Any required stack pointer alignment is preserved. 1147 1148 SIZE is an rtx representing the size of the area. 1149 1150 SIZE_ALIGN is the alignment (in bits) that we know SIZE has. This 1151 parameter may be zero. If so, a proper value will be extracted 1152 from SIZE if it is constant, otherwise BITS_PER_UNIT will be assumed. 1153 1154 REQUIRED_ALIGN is the alignment (in bits) required for the region 1155 of memory. 1156 1157 If CANNOT_ACCUMULATE is set to TRUE, the caller guarantees that the 1158 stack space allocated by the generated code cannot be added with itself 1159 in the course of the execution of the function. It is always safe to 1160 pass FALSE here and the following criterion is sufficient in order to 1161 pass TRUE: every path in the CFG that starts at the allocation point and 1162 loops to it executes the associated deallocation code. */ 1163 1164 rtx 1165 allocate_dynamic_stack_space (rtx size, unsigned size_align, 1166 unsigned required_align, bool cannot_accumulate) 1167 { 1168 HOST_WIDE_INT stack_usage_size = -1; 1169 rtx final_label, final_target, target; 1170 unsigned extra_align = 0; 1171 bool must_align; 1172 1173 /* If we're asking for zero bytes, it doesn't matter what we point 1174 to since we can't dereference it. But return a reasonable 1175 address anyway. */ 1176 if (size == const0_rtx) 1177 return virtual_stack_dynamic_rtx; 1178 1179 /* Otherwise, show we're calling alloca or equivalent. */ 1180 cfun->calls_alloca = 1; 1181 1182 /* If stack usage info is requested, look into the size we are passed. 1183 We need to do so this early to avoid the obfuscation that may be 1184 introduced later by the various alignment operations. */ 1185 if (flag_stack_usage_info) 1186 { 1187 if (CONST_INT_P (size)) 1188 stack_usage_size = INTVAL (size); 1189 else if (REG_P (size)) 1190 { 1191 /* Look into the last emitted insn and see if we can deduce 1192 something for the register. */ 1193 rtx insn, set, note; 1194 insn = get_last_insn (); 1195 if ((set = single_set (insn)) && rtx_equal_p (SET_DEST (set), size)) 1196 { 1197 if (CONST_INT_P (SET_SRC (set))) 1198 stack_usage_size = INTVAL (SET_SRC (set)); 1199 else if ((note = find_reg_equal_equiv_note (insn)) 1200 && CONST_INT_P (XEXP (note, 0))) 1201 stack_usage_size = INTVAL (XEXP (note, 0)); 1202 } 1203 } 1204 1205 /* If the size is not constant, we can't say anything. */ 1206 if (stack_usage_size == -1) 1207 { 1208 current_function_has_unbounded_dynamic_stack_size = 1; 1209 stack_usage_size = 0; 1210 } 1211 } 1212 1213 /* Ensure the size is in the proper mode. */ 1214 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode) 1215 size = convert_to_mode (Pmode, size, 1); 1216 1217 /* Adjust SIZE_ALIGN, if needed. */ 1218 if (CONST_INT_P (size)) 1219 { 1220 unsigned HOST_WIDE_INT lsb; 1221 1222 lsb = INTVAL (size); 1223 lsb &= -lsb; 1224 1225 /* Watch out for overflow truncating to "unsigned". */ 1226 if (lsb > UINT_MAX / BITS_PER_UNIT) 1227 size_align = 1u << (HOST_BITS_PER_INT - 1); 1228 else 1229 size_align = (unsigned)lsb * BITS_PER_UNIT; 1230 } 1231 else if (size_align < BITS_PER_UNIT) 1232 size_align = BITS_PER_UNIT; 1233 1234 /* We can't attempt to minimize alignment necessary, because we don't 1235 know the final value of preferred_stack_boundary yet while executing 1236 this code. */ 1237 if (crtl->preferred_stack_boundary < PREFERRED_STACK_BOUNDARY) 1238 crtl->preferred_stack_boundary = PREFERRED_STACK_BOUNDARY; 1239 1240 /* We will need to ensure that the address we return is aligned to 1241 REQUIRED_ALIGN. If STACK_DYNAMIC_OFFSET is defined, we don't 1242 always know its final value at this point in the compilation (it 1243 might depend on the size of the outgoing parameter lists, for 1244 example), so we must align the value to be returned in that case. 1245 (Note that STACK_DYNAMIC_OFFSET will have a default nonzero value if 1246 STACK_POINTER_OFFSET or ACCUMULATE_OUTGOING_ARGS are defined). 1247 We must also do an alignment operation on the returned value if 1248 the stack pointer alignment is less strict than REQUIRED_ALIGN. 1249 1250 If we have to align, we must leave space in SIZE for the hole 1251 that might result from the alignment operation. */ 1252 1253 must_align = (crtl->preferred_stack_boundary < required_align); 1254 if (must_align) 1255 { 1256 if (required_align > PREFERRED_STACK_BOUNDARY) 1257 extra_align = PREFERRED_STACK_BOUNDARY; 1258 else if (required_align > STACK_BOUNDARY) 1259 extra_align = STACK_BOUNDARY; 1260 else 1261 extra_align = BITS_PER_UNIT; 1262 } 1263 1264 /* ??? STACK_POINTER_OFFSET is always defined now. */ 1265 #if defined (STACK_DYNAMIC_OFFSET) || defined (STACK_POINTER_OFFSET) 1266 must_align = true; 1267 extra_align = BITS_PER_UNIT; 1268 #endif 1269 1270 if (must_align) 1271 { 1272 unsigned extra = (required_align - extra_align) / BITS_PER_UNIT; 1273 1274 size = plus_constant (Pmode, size, extra); 1275 size = force_operand (size, NULL_RTX); 1276 1277 if (flag_stack_usage_info) 1278 stack_usage_size += extra; 1279 1280 if (extra && size_align > extra_align) 1281 size_align = extra_align; 1282 } 1283 1284 /* Round the size to a multiple of the required stack alignment. 1285 Since the stack if presumed to be rounded before this allocation, 1286 this will maintain the required alignment. 1287 1288 If the stack grows downward, we could save an insn by subtracting 1289 SIZE from the stack pointer and then aligning the stack pointer. 1290 The problem with this is that the stack pointer may be unaligned 1291 between the execution of the subtraction and alignment insns and 1292 some machines do not allow this. Even on those that do, some 1293 signal handlers malfunction if a signal should occur between those 1294 insns. Since this is an extremely rare event, we have no reliable 1295 way of knowing which systems have this problem. So we avoid even 1296 momentarily mis-aligning the stack. */ 1297 if (size_align % MAX_SUPPORTED_STACK_ALIGNMENT != 0) 1298 { 1299 size = round_push (size); 1300 1301 if (flag_stack_usage_info) 1302 { 1303 int align = crtl->preferred_stack_boundary / BITS_PER_UNIT; 1304 stack_usage_size = (stack_usage_size + align - 1) / align * align; 1305 } 1306 } 1307 1308 target = gen_reg_rtx (Pmode); 1309 1310 /* The size is supposed to be fully adjusted at this point so record it 1311 if stack usage info is requested. */ 1312 if (flag_stack_usage_info) 1313 { 1314 current_function_dynamic_stack_size += stack_usage_size; 1315 1316 /* ??? This is gross but the only safe stance in the absence 1317 of stack usage oriented flow analysis. */ 1318 if (!cannot_accumulate) 1319 current_function_has_unbounded_dynamic_stack_size = 1; 1320 } 1321 1322 final_label = NULL_RTX; 1323 final_target = NULL_RTX; 1324 1325 /* If we are splitting the stack, we need to ask the backend whether 1326 there is enough room on the current stack. If there isn't, or if 1327 the backend doesn't know how to tell is, then we need to call a 1328 function to allocate memory in some other way. This memory will 1329 be released when we release the current stack segment. The 1330 effect is that stack allocation becomes less efficient, but at 1331 least it doesn't cause a stack overflow. */ 1332 if (flag_split_stack) 1333 { 1334 rtx available_label, ask, space, func; 1335 1336 available_label = NULL_RTX; 1337 1338 #ifdef HAVE_split_stack_space_check 1339 if (HAVE_split_stack_space_check) 1340 { 1341 available_label = gen_label_rtx (); 1342 1343 /* This instruction will branch to AVAILABLE_LABEL if there 1344 are SIZE bytes available on the stack. */ 1345 emit_insn (gen_split_stack_space_check (size, available_label)); 1346 } 1347 #endif 1348 1349 /* The __morestack_allocate_stack_space function will allocate 1350 memory using malloc. If the alignment of the memory returned 1351 by malloc does not meet REQUIRED_ALIGN, we increase SIZE to 1352 make sure we allocate enough space. */ 1353 if (MALLOC_ABI_ALIGNMENT >= required_align) 1354 ask = size; 1355 else 1356 { 1357 ask = expand_binop (Pmode, add_optab, size, 1358 GEN_INT (required_align / BITS_PER_UNIT - 1), 1359 NULL_RTX, 1, OPTAB_LIB_WIDEN); 1360 must_align = true; 1361 } 1362 1363 func = init_one_libfunc ("__morestack_allocate_stack_space"); 1364 1365 space = emit_library_call_value (func, target, LCT_NORMAL, Pmode, 1366 1, ask, Pmode); 1367 1368 if (available_label == NULL_RTX) 1369 return space; 1370 1371 final_target = gen_reg_rtx (Pmode); 1372 1373 emit_move_insn (final_target, space); 1374 1375 final_label = gen_label_rtx (); 1376 emit_jump (final_label); 1377 1378 emit_label (available_label); 1379 } 1380 1381 do_pending_stack_adjust (); 1382 1383 /* We ought to be called always on the toplevel and stack ought to be aligned 1384 properly. */ 1385 gcc_assert (!(stack_pointer_delta 1386 % (PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT))); 1387 1388 /* If needed, check that we have the required amount of stack. Take into 1389 account what has already been checked. */ 1390 if (STACK_CHECK_MOVING_SP) 1391 ; 1392 else if (flag_stack_check == GENERIC_STACK_CHECK) 1393 probe_stack_range (STACK_OLD_CHECK_PROTECT + STACK_CHECK_MAX_FRAME_SIZE, 1394 size); 1395 else if (flag_stack_check == STATIC_BUILTIN_STACK_CHECK) 1396 probe_stack_range (STACK_CHECK_PROTECT, size); 1397 1398 /* Don't let anti_adjust_stack emit notes. */ 1399 suppress_reg_args_size = true; 1400 1401 /* Perform the required allocation from the stack. Some systems do 1402 this differently than simply incrementing/decrementing from the 1403 stack pointer, such as acquiring the space by calling malloc(). */ 1404 #ifdef HAVE_allocate_stack 1405 if (HAVE_allocate_stack) 1406 { 1407 struct expand_operand ops[2]; 1408 /* We don't have to check against the predicate for operand 0 since 1409 TARGET is known to be a pseudo of the proper mode, which must 1410 be valid for the operand. */ 1411 create_fixed_operand (&ops[0], target); 1412 create_convert_operand_to (&ops[1], size, STACK_SIZE_MODE, true); 1413 expand_insn (CODE_FOR_allocate_stack, 2, ops); 1414 } 1415 else 1416 #endif 1417 { 1418 int saved_stack_pointer_delta; 1419 1420 #ifndef STACK_GROWS_DOWNWARD 1421 emit_move_insn (target, virtual_stack_dynamic_rtx); 1422 #endif 1423 1424 /* Check stack bounds if necessary. */ 1425 if (crtl->limit_stack) 1426 { 1427 rtx available; 1428 rtx space_available = gen_label_rtx (); 1429 #ifdef STACK_GROWS_DOWNWARD 1430 available = expand_binop (Pmode, sub_optab, 1431 stack_pointer_rtx, stack_limit_rtx, 1432 NULL_RTX, 1, OPTAB_WIDEN); 1433 #else 1434 available = expand_binop (Pmode, sub_optab, 1435 stack_limit_rtx, stack_pointer_rtx, 1436 NULL_RTX, 1, OPTAB_WIDEN); 1437 #endif 1438 emit_cmp_and_jump_insns (available, size, GEU, NULL_RTX, Pmode, 1, 1439 space_available); 1440 #ifdef HAVE_trap 1441 if (HAVE_trap) 1442 emit_insn (gen_trap ()); 1443 else 1444 #endif 1445 error ("stack limits not supported on this target"); 1446 emit_barrier (); 1447 emit_label (space_available); 1448 } 1449 1450 saved_stack_pointer_delta = stack_pointer_delta; 1451 1452 if (flag_stack_check && STACK_CHECK_MOVING_SP) 1453 anti_adjust_stack_and_probe (size, false); 1454 else 1455 anti_adjust_stack (size); 1456 1457 /* Even if size is constant, don't modify stack_pointer_delta. 1458 The constant size alloca should preserve 1459 crtl->preferred_stack_boundary alignment. */ 1460 stack_pointer_delta = saved_stack_pointer_delta; 1461 1462 #ifdef STACK_GROWS_DOWNWARD 1463 emit_move_insn (target, virtual_stack_dynamic_rtx); 1464 #endif 1465 } 1466 1467 suppress_reg_args_size = false; 1468 1469 /* Finish up the split stack handling. */ 1470 if (final_label != NULL_RTX) 1471 { 1472 gcc_assert (flag_split_stack); 1473 emit_move_insn (final_target, target); 1474 emit_label (final_label); 1475 target = final_target; 1476 } 1477 1478 if (must_align) 1479 { 1480 /* CEIL_DIV_EXPR needs to worry about the addition overflowing, 1481 but we know it can't. So add ourselves and then do 1482 TRUNC_DIV_EXPR. */ 1483 target = expand_binop (Pmode, add_optab, target, 1484 GEN_INT (required_align / BITS_PER_UNIT - 1), 1485 NULL_RTX, 1, OPTAB_LIB_WIDEN); 1486 target = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, target, 1487 GEN_INT (required_align / BITS_PER_UNIT), 1488 NULL_RTX, 1); 1489 target = expand_mult (Pmode, target, 1490 GEN_INT (required_align / BITS_PER_UNIT), 1491 NULL_RTX, 1); 1492 } 1493 1494 /* Now that we've committed to a return value, mark its alignment. */ 1495 mark_reg_pointer (target, required_align); 1496 1497 /* Record the new stack level for nonlocal gotos. */ 1498 if (cfun->nonlocal_goto_save_area != 0) 1499 update_nonlocal_goto_save_area (); 1500 1501 return target; 1502 } 1503 1504 /* A front end may want to override GCC's stack checking by providing a 1505 run-time routine to call to check the stack, so provide a mechanism for 1506 calling that routine. */ 1507 1508 static GTY(()) rtx stack_check_libfunc; 1509 1510 void 1511 set_stack_check_libfunc (const char *libfunc_name) 1512 { 1513 gcc_assert (stack_check_libfunc == NULL_RTX); 1514 stack_check_libfunc = gen_rtx_SYMBOL_REF (Pmode, libfunc_name); 1515 } 1516 1517 /* Emit one stack probe at ADDRESS, an address within the stack. */ 1518 1519 void 1520 emit_stack_probe (rtx address) 1521 { 1522 #ifdef HAVE_probe_stack_address 1523 if (HAVE_probe_stack_address) 1524 emit_insn (gen_probe_stack_address (address)); 1525 else 1526 #endif 1527 { 1528 rtx memref = gen_rtx_MEM (word_mode, address); 1529 1530 MEM_VOLATILE_P (memref) = 1; 1531 1532 /* See if we have an insn to probe the stack. */ 1533 #ifdef HAVE_probe_stack 1534 if (HAVE_probe_stack) 1535 emit_insn (gen_probe_stack (memref)); 1536 else 1537 #endif 1538 emit_move_insn (memref, const0_rtx); 1539 } 1540 } 1541 1542 /* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive. 1543 FIRST is a constant and size is a Pmode RTX. These are offsets from 1544 the current stack pointer. STACK_GROWS_DOWNWARD says whether to add 1545 or subtract them from the stack pointer. */ 1546 1547 #define PROBE_INTERVAL (1 << STACK_CHECK_PROBE_INTERVAL_EXP) 1548 1549 #ifdef STACK_GROWS_DOWNWARD 1550 #define STACK_GROW_OP MINUS 1551 #define STACK_GROW_OPTAB sub_optab 1552 #define STACK_GROW_OFF(off) -(off) 1553 #else 1554 #define STACK_GROW_OP PLUS 1555 #define STACK_GROW_OPTAB add_optab 1556 #define STACK_GROW_OFF(off) (off) 1557 #endif 1558 1559 void 1560 probe_stack_range (HOST_WIDE_INT first, rtx size) 1561 { 1562 /* First ensure SIZE is Pmode. */ 1563 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode) 1564 size = convert_to_mode (Pmode, size, 1); 1565 1566 /* Next see if we have a function to check the stack. */ 1567 if (stack_check_libfunc) 1568 { 1569 rtx addr = memory_address (Pmode, 1570 gen_rtx_fmt_ee (STACK_GROW_OP, Pmode, 1571 stack_pointer_rtx, 1572 plus_constant (Pmode, 1573 size, first))); 1574 emit_library_call (stack_check_libfunc, LCT_NORMAL, VOIDmode, 1, addr, 1575 Pmode); 1576 } 1577 1578 /* Next see if we have an insn to check the stack. */ 1579 #ifdef HAVE_check_stack 1580 else if (HAVE_check_stack) 1581 { 1582 struct expand_operand ops[1]; 1583 rtx addr = memory_address (Pmode, 1584 gen_rtx_fmt_ee (STACK_GROW_OP, Pmode, 1585 stack_pointer_rtx, 1586 plus_constant (Pmode, 1587 size, first))); 1588 bool success; 1589 create_input_operand (&ops[0], addr, Pmode); 1590 success = maybe_expand_insn (CODE_FOR_check_stack, 1, ops); 1591 gcc_assert (success); 1592 } 1593 #endif 1594 1595 /* Otherwise we have to generate explicit probes. If we have a constant 1596 small number of them to generate, that's the easy case. */ 1597 else if (CONST_INT_P (size) && INTVAL (size) < 7 * PROBE_INTERVAL) 1598 { 1599 HOST_WIDE_INT isize = INTVAL (size), i; 1600 rtx addr; 1601 1602 /* Probe at FIRST + N * PROBE_INTERVAL for values of N from 1 until 1603 it exceeds SIZE. If only one probe is needed, this will not 1604 generate any code. Then probe at FIRST + SIZE. */ 1605 for (i = PROBE_INTERVAL; i < isize; i += PROBE_INTERVAL) 1606 { 1607 addr = memory_address (Pmode, 1608 plus_constant (Pmode, stack_pointer_rtx, 1609 STACK_GROW_OFF (first + i))); 1610 emit_stack_probe (addr); 1611 } 1612 1613 addr = memory_address (Pmode, 1614 plus_constant (Pmode, stack_pointer_rtx, 1615 STACK_GROW_OFF (first + isize))); 1616 emit_stack_probe (addr); 1617 } 1618 1619 /* In the variable case, do the same as above, but in a loop. Note that we 1620 must be extra careful with variables wrapping around because we might be 1621 at the very top (or the very bottom) of the address space and we have to 1622 be able to handle this case properly; in particular, we use an equality 1623 test for the loop condition. */ 1624 else 1625 { 1626 rtx rounded_size, rounded_size_op, test_addr, last_addr, temp; 1627 rtx loop_lab = gen_label_rtx (); 1628 rtx end_lab = gen_label_rtx (); 1629 1630 1631 /* Step 1: round SIZE to the previous multiple of the interval. */ 1632 1633 /* ROUNDED_SIZE = SIZE & -PROBE_INTERVAL */ 1634 rounded_size 1635 = simplify_gen_binary (AND, Pmode, size, GEN_INT (-PROBE_INTERVAL)); 1636 rounded_size_op = force_operand (rounded_size, NULL_RTX); 1637 1638 1639 /* Step 2: compute initial and final value of the loop counter. */ 1640 1641 /* TEST_ADDR = SP + FIRST. */ 1642 test_addr = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode, 1643 stack_pointer_rtx, 1644 GEN_INT (first)), NULL_RTX); 1645 1646 /* LAST_ADDR = SP + FIRST + ROUNDED_SIZE. */ 1647 last_addr = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode, 1648 test_addr, 1649 rounded_size_op), NULL_RTX); 1650 1651 1652 /* Step 3: the loop 1653 1654 while (TEST_ADDR != LAST_ADDR) 1655 { 1656 TEST_ADDR = TEST_ADDR + PROBE_INTERVAL 1657 probe at TEST_ADDR 1658 } 1659 1660 probes at FIRST + N * PROBE_INTERVAL for values of N from 1 1661 until it is equal to ROUNDED_SIZE. */ 1662 1663 emit_label (loop_lab); 1664 1665 /* Jump to END_LAB if TEST_ADDR == LAST_ADDR. */ 1666 emit_cmp_and_jump_insns (test_addr, last_addr, EQ, NULL_RTX, Pmode, 1, 1667 end_lab); 1668 1669 /* TEST_ADDR = TEST_ADDR + PROBE_INTERVAL. */ 1670 temp = expand_binop (Pmode, STACK_GROW_OPTAB, test_addr, 1671 GEN_INT (PROBE_INTERVAL), test_addr, 1672 1, OPTAB_WIDEN); 1673 1674 gcc_assert (temp == test_addr); 1675 1676 /* Probe at TEST_ADDR. */ 1677 emit_stack_probe (test_addr); 1678 1679 emit_jump (loop_lab); 1680 1681 emit_label (end_lab); 1682 1683 1684 /* Step 4: probe at FIRST + SIZE if we cannot assert at compile-time 1685 that SIZE is equal to ROUNDED_SIZE. */ 1686 1687 /* TEMP = SIZE - ROUNDED_SIZE. */ 1688 temp = simplify_gen_binary (MINUS, Pmode, size, rounded_size); 1689 if (temp != const0_rtx) 1690 { 1691 rtx addr; 1692 1693 if (CONST_INT_P (temp)) 1694 { 1695 /* Use [base + disp} addressing mode if supported. */ 1696 HOST_WIDE_INT offset = INTVAL (temp); 1697 addr = memory_address (Pmode, 1698 plus_constant (Pmode, last_addr, 1699 STACK_GROW_OFF (offset))); 1700 } 1701 else 1702 { 1703 /* Manual CSE if the difference is not known at compile-time. */ 1704 temp = gen_rtx_MINUS (Pmode, size, rounded_size_op); 1705 addr = memory_address (Pmode, 1706 gen_rtx_fmt_ee (STACK_GROW_OP, Pmode, 1707 last_addr, temp)); 1708 } 1709 1710 emit_stack_probe (addr); 1711 } 1712 } 1713 } 1714 1715 /* Adjust the stack pointer by minus SIZE (an rtx for a number of bytes) 1716 while probing it. This pushes when SIZE is positive. SIZE need not 1717 be constant. If ADJUST_BACK is true, adjust back the stack pointer 1718 by plus SIZE at the end. */ 1719 1720 void 1721 anti_adjust_stack_and_probe (rtx size, bool adjust_back) 1722 { 1723 /* We skip the probe for the first interval + a small dope of 4 words and 1724 probe that many bytes past the specified size to maintain a protection 1725 area at the botton of the stack. */ 1726 const int dope = 4 * UNITS_PER_WORD; 1727 1728 /* First ensure SIZE is Pmode. */ 1729 if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode) 1730 size = convert_to_mode (Pmode, size, 1); 1731 1732 /* If we have a constant small number of probes to generate, that's the 1733 easy case. */ 1734 if (CONST_INT_P (size) && INTVAL (size) < 7 * PROBE_INTERVAL) 1735 { 1736 HOST_WIDE_INT isize = INTVAL (size), i; 1737 bool first_probe = true; 1738 1739 /* Adjust SP and probe at PROBE_INTERVAL + N * PROBE_INTERVAL for 1740 values of N from 1 until it exceeds SIZE. If only one probe is 1741 needed, this will not generate any code. Then adjust and probe 1742 to PROBE_INTERVAL + SIZE. */ 1743 for (i = PROBE_INTERVAL; i < isize; i += PROBE_INTERVAL) 1744 { 1745 if (first_probe) 1746 { 1747 anti_adjust_stack (GEN_INT (2 * PROBE_INTERVAL + dope)); 1748 first_probe = false; 1749 } 1750 else 1751 anti_adjust_stack (GEN_INT (PROBE_INTERVAL)); 1752 emit_stack_probe (stack_pointer_rtx); 1753 } 1754 1755 if (first_probe) 1756 anti_adjust_stack (plus_constant (Pmode, size, PROBE_INTERVAL + dope)); 1757 else 1758 anti_adjust_stack (plus_constant (Pmode, size, PROBE_INTERVAL - i)); 1759 emit_stack_probe (stack_pointer_rtx); 1760 } 1761 1762 /* In the variable case, do the same as above, but in a loop. Note that we 1763 must be extra careful with variables wrapping around because we might be 1764 at the very top (or the very bottom) of the address space and we have to 1765 be able to handle this case properly; in particular, we use an equality 1766 test for the loop condition. */ 1767 else 1768 { 1769 rtx rounded_size, rounded_size_op, last_addr, temp; 1770 rtx loop_lab = gen_label_rtx (); 1771 rtx end_lab = gen_label_rtx (); 1772 1773 1774 /* Step 1: round SIZE to the previous multiple of the interval. */ 1775 1776 /* ROUNDED_SIZE = SIZE & -PROBE_INTERVAL */ 1777 rounded_size 1778 = simplify_gen_binary (AND, Pmode, size, GEN_INT (-PROBE_INTERVAL)); 1779 rounded_size_op = force_operand (rounded_size, NULL_RTX); 1780 1781 1782 /* Step 2: compute initial and final value of the loop counter. */ 1783 1784 /* SP = SP_0 + PROBE_INTERVAL. */ 1785 anti_adjust_stack (GEN_INT (PROBE_INTERVAL + dope)); 1786 1787 /* LAST_ADDR = SP_0 + PROBE_INTERVAL + ROUNDED_SIZE. */ 1788 last_addr = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode, 1789 stack_pointer_rtx, 1790 rounded_size_op), NULL_RTX); 1791 1792 1793 /* Step 3: the loop 1794 1795 while (SP != LAST_ADDR) 1796 { 1797 SP = SP + PROBE_INTERVAL 1798 probe at SP 1799 } 1800 1801 adjusts SP and probes at PROBE_INTERVAL + N * PROBE_INTERVAL for 1802 values of N from 1 until it is equal to ROUNDED_SIZE. */ 1803 1804 emit_label (loop_lab); 1805 1806 /* Jump to END_LAB if SP == LAST_ADDR. */ 1807 emit_cmp_and_jump_insns (stack_pointer_rtx, last_addr, EQ, NULL_RTX, 1808 Pmode, 1, end_lab); 1809 1810 /* SP = SP + PROBE_INTERVAL and probe at SP. */ 1811 anti_adjust_stack (GEN_INT (PROBE_INTERVAL)); 1812 emit_stack_probe (stack_pointer_rtx); 1813 1814 emit_jump (loop_lab); 1815 1816 emit_label (end_lab); 1817 1818 1819 /* Step 4: adjust SP and probe at PROBE_INTERVAL + SIZE if we cannot 1820 assert at compile-time that SIZE is equal to ROUNDED_SIZE. */ 1821 1822 /* TEMP = SIZE - ROUNDED_SIZE. */ 1823 temp = simplify_gen_binary (MINUS, Pmode, size, rounded_size); 1824 if (temp != const0_rtx) 1825 { 1826 /* Manual CSE if the difference is not known at compile-time. */ 1827 if (GET_CODE (temp) != CONST_INT) 1828 temp = gen_rtx_MINUS (Pmode, size, rounded_size_op); 1829 anti_adjust_stack (temp); 1830 emit_stack_probe (stack_pointer_rtx); 1831 } 1832 } 1833 1834 /* Adjust back and account for the additional first interval. */ 1835 if (adjust_back) 1836 adjust_stack (plus_constant (Pmode, size, PROBE_INTERVAL + dope)); 1837 else 1838 adjust_stack (GEN_INT (PROBE_INTERVAL + dope)); 1839 } 1840 1841 /* Return an rtx representing the register or memory location 1842 in which a scalar value of data type VALTYPE 1843 was returned by a function call to function FUNC. 1844 FUNC is a FUNCTION_DECL, FNTYPE a FUNCTION_TYPE node if the precise 1845 function is known, otherwise 0. 1846 OUTGOING is 1 if on a machine with register windows this function 1847 should return the register in which the function will put its result 1848 and 0 otherwise. */ 1849 1850 rtx 1851 hard_function_value (const_tree valtype, const_tree func, const_tree fntype, 1852 int outgoing ATTRIBUTE_UNUSED) 1853 { 1854 rtx val; 1855 1856 val = targetm.calls.function_value (valtype, func ? func : fntype, outgoing); 1857 1858 if (REG_P (val) 1859 && GET_MODE (val) == BLKmode) 1860 { 1861 unsigned HOST_WIDE_INT bytes = int_size_in_bytes (valtype); 1862 enum machine_mode tmpmode; 1863 1864 /* int_size_in_bytes can return -1. We don't need a check here 1865 since the value of bytes will then be large enough that no 1866 mode will match anyway. */ 1867 1868 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT); 1869 tmpmode != VOIDmode; 1870 tmpmode = GET_MODE_WIDER_MODE (tmpmode)) 1871 { 1872 /* Have we found a large enough mode? */ 1873 if (GET_MODE_SIZE (tmpmode) >= bytes) 1874 break; 1875 } 1876 1877 /* No suitable mode found. */ 1878 gcc_assert (tmpmode != VOIDmode); 1879 1880 PUT_MODE (val, tmpmode); 1881 } 1882 return val; 1883 } 1884 1885 /* Return an rtx representing the register or memory location 1886 in which a scalar value of mode MODE was returned by a library call. */ 1887 1888 rtx 1889 hard_libcall_value (enum machine_mode mode, rtx fun) 1890 { 1891 return targetm.calls.libcall_value (mode, fun); 1892 } 1893 1894 /* Look up the tree code for a given rtx code 1895 to provide the arithmetic operation for REAL_ARITHMETIC. 1896 The function returns an int because the caller may not know 1897 what `enum tree_code' means. */ 1898 1899 int 1900 rtx_to_tree_code (enum rtx_code code) 1901 { 1902 enum tree_code tcode; 1903 1904 switch (code) 1905 { 1906 case PLUS: 1907 tcode = PLUS_EXPR; 1908 break; 1909 case MINUS: 1910 tcode = MINUS_EXPR; 1911 break; 1912 case MULT: 1913 tcode = MULT_EXPR; 1914 break; 1915 case DIV: 1916 tcode = RDIV_EXPR; 1917 break; 1918 case SMIN: 1919 tcode = MIN_EXPR; 1920 break; 1921 case SMAX: 1922 tcode = MAX_EXPR; 1923 break; 1924 default: 1925 tcode = LAST_AND_UNUSED_TREE_CODE; 1926 break; 1927 } 1928 return ((int) tcode); 1929 } 1930 1931 #include "gt-explow.h" 1932