1 /* Subroutines for manipulating rtx's in semantically interesting ways.
2 Copyright (C) 1987-2017 Free Software Foundation, Inc.
4 This file is part of GCC.
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
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
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/>. */
23 #include "coretypes.h"
31 #include "profile-count.h"
35 #include "diagnostic-core.h"
36 #include "stor-layout.h"
41 #include "common/common-target.h"
45 static rtx
break_out_memory_refs (rtx
);
46 static void anti_adjust_stack_and_probe_stack_clash (rtx
);
49 /* Truncate and perhaps sign-extend C as appropriate for MODE. */
52 trunc_int_for_mode (HOST_WIDE_INT c
, machine_mode mode
)
54 /* Not scalar_int_mode because we also allow pointer bound modes. */
55 scalar_mode smode
= as_a
<scalar_mode
> (mode
);
56 int width
= GET_MODE_PRECISION (smode
);
58 /* You want to truncate to a _what_? */
59 gcc_assert (SCALAR_INT_MODE_P (mode
)
60 || POINTER_BOUNDS_MODE_P (mode
));
62 /* Canonicalize BImode to 0 and STORE_FLAG_VALUE. */
64 return c
& 1 ? STORE_FLAG_VALUE
: 0;
66 /* Sign-extend for the requested mode. */
68 if (width
< HOST_BITS_PER_WIDE_INT
)
70 HOST_WIDE_INT sign
= 1;
80 /* Return an rtx for the sum of X and the integer C, given that X has
81 mode MODE. INPLACE is true if X can be modified inplace or false
82 if it must be treated as immutable. */
85 plus_constant (machine_mode mode
, rtx x
, HOST_WIDE_INT c
,
93 gcc_assert (GET_MODE (x
) == VOIDmode
|| GET_MODE (x
) == mode
);
105 CASE_CONST_SCALAR_INT
:
106 return immed_wide_int_const (wi::add (rtx_mode_t (x
, mode
), c
), mode
);
108 /* If this is a reference to the constant pool, try replacing it with
109 a reference to a new constant. If the resulting address isn't
110 valid, don't return it because we have no way to validize it. */
111 if (GET_CODE (XEXP (x
, 0)) == SYMBOL_REF
112 && CONSTANT_POOL_ADDRESS_P (XEXP (x
, 0)))
114 rtx cst
= get_pool_constant (XEXP (x
, 0));
116 if (GET_CODE (cst
) == CONST_VECTOR
117 && GET_MODE_INNER (GET_MODE (cst
)) == mode
)
119 cst
= gen_lowpart (mode
, cst
);
122 if (GET_MODE (cst
) == VOIDmode
|| GET_MODE (cst
) == mode
)
124 tem
= plus_constant (mode
, cst
, c
);
125 tem
= force_const_mem (GET_MODE (x
), tem
);
126 /* Targets may disallow some constants in the constant pool, thus
127 force_const_mem may return NULL_RTX. */
128 if (tem
&& memory_address_p (GET_MODE (tem
), XEXP (tem
, 0)))
135 /* If adding to something entirely constant, set a flag
136 so that we can add a CONST around the result. */
137 if (inplace
&& shared_const_p (x
))
149 /* The interesting case is adding the integer to a sum. Look
150 for constant term in the sum and combine with C. For an
151 integer constant term or a constant term that is not an
152 explicit integer, we combine or group them together anyway.
154 We may not immediately return from the recursive call here, lest
155 all_constant gets lost. */
157 if (CONSTANT_P (XEXP (x
, 1)))
159 rtx term
= plus_constant (mode
, XEXP (x
, 1), c
, inplace
);
160 if (term
== const0_rtx
)
165 x
= gen_rtx_PLUS (mode
, XEXP (x
, 0), term
);
168 else if (rtx
*const_loc
= find_constant_term_loc (&y
))
172 /* We need to be careful since X may be shared and we can't
173 modify it in place. */
175 const_loc
= find_constant_term_loc (&x
);
177 *const_loc
= plus_constant (mode
, *const_loc
, c
, true);
187 x
= gen_rtx_PLUS (mode
, x
, gen_int_mode (c
, mode
));
189 if (GET_CODE (x
) == SYMBOL_REF
|| GET_CODE (x
) == LABEL_REF
)
191 else if (all_constant
)
192 return gen_rtx_CONST (mode
, x
);
197 /* If X is a sum, return a new sum like X but lacking any constant terms.
198 Add all the removed constant terms into *CONSTPTR.
199 X itself is not altered. The result != X if and only if
200 it is not isomorphic to X. */
203 eliminate_constant_term (rtx x
, rtx
*constptr
)
208 if (GET_CODE (x
) != PLUS
)
211 /* First handle constants appearing at this level explicitly. */
212 if (CONST_INT_P (XEXP (x
, 1))
213 && 0 != (tem
= simplify_binary_operation (PLUS
, GET_MODE (x
), *constptr
,
215 && CONST_INT_P (tem
))
218 return eliminate_constant_term (XEXP (x
, 0), constptr
);
222 x0
= eliminate_constant_term (XEXP (x
, 0), &tem
);
223 x1
= eliminate_constant_term (XEXP (x
, 1), &tem
);
224 if ((x1
!= XEXP (x
, 1) || x0
!= XEXP (x
, 0))
225 && 0 != (tem
= simplify_binary_operation (PLUS
, GET_MODE (x
),
227 && CONST_INT_P (tem
))
230 return gen_rtx_PLUS (GET_MODE (x
), x0
, x1
);
237 /* Return a copy of X in which all memory references
238 and all constants that involve symbol refs
239 have been replaced with new temporary registers.
240 Also emit code to load the memory locations and constants
241 into those registers.
243 If X contains no such constants or memory references,
244 X itself (not a copy) is returned.
246 If a constant is found in the address that is not a legitimate constant
247 in an insn, it is left alone in the hope that it might be valid in the
250 X may contain no arithmetic except addition, subtraction and multiplication.
251 Values returned by expand_expr with 1 for sum_ok fit this constraint. */
254 break_out_memory_refs (rtx x
)
257 || (CONSTANT_P (x
) && CONSTANT_ADDRESS_P (x
)
258 && GET_MODE (x
) != VOIDmode
))
259 x
= force_reg (GET_MODE (x
), x
);
260 else if (GET_CODE (x
) == PLUS
|| GET_CODE (x
) == MINUS
261 || GET_CODE (x
) == MULT
)
263 rtx op0
= break_out_memory_refs (XEXP (x
, 0));
264 rtx op1
= break_out_memory_refs (XEXP (x
, 1));
266 if (op0
!= XEXP (x
, 0) || op1
!= XEXP (x
, 1))
267 x
= simplify_gen_binary (GET_CODE (x
), GET_MODE (x
), op0
, op1
);
273 /* Given X, a memory address in address space AS' pointer mode, convert it to
274 an address in the address space's address mode, or vice versa (TO_MODE says
275 which way). We take advantage of the fact that pointers are not allowed to
276 overflow by commuting arithmetic operations over conversions so that address
277 arithmetic insns can be used. IN_CONST is true if this conversion is inside
278 a CONST. NO_EMIT is true if no insns should be emitted, and instead
279 it should return NULL if it can't be simplified without emitting insns. */
282 convert_memory_address_addr_space_1 (scalar_int_mode to_mode ATTRIBUTE_UNUSED
,
283 rtx x
, addr_space_t as ATTRIBUTE_UNUSED
,
284 bool in_const ATTRIBUTE_UNUSED
,
285 bool no_emit ATTRIBUTE_UNUSED
)
287 #ifndef POINTERS_EXTEND_UNSIGNED
288 gcc_assert (GET_MODE (x
) == to_mode
|| GET_MODE (x
) == VOIDmode
);
290 #else /* defined(POINTERS_EXTEND_UNSIGNED) */
291 scalar_int_mode pointer_mode
, address_mode
, from_mode
;
295 /* If X already has the right mode, just return it. */
296 if (GET_MODE (x
) == to_mode
)
299 pointer_mode
= targetm
.addr_space
.pointer_mode (as
);
300 address_mode
= targetm
.addr_space
.address_mode (as
);
301 from_mode
= to_mode
== pointer_mode
? address_mode
: pointer_mode
;
303 /* Here we handle some special cases. If none of them apply, fall through
304 to the default case. */
305 switch (GET_CODE (x
))
307 CASE_CONST_SCALAR_INT
:
308 if (GET_MODE_SIZE (to_mode
) < GET_MODE_SIZE (from_mode
))
310 else if (POINTERS_EXTEND_UNSIGNED
< 0)
312 else if (POINTERS_EXTEND_UNSIGNED
> 0)
316 temp
= simplify_unary_operation (code
, to_mode
, x
, from_mode
);
322 if ((SUBREG_PROMOTED_VAR_P (x
) || REG_POINTER (SUBREG_REG (x
)))
323 && GET_MODE (SUBREG_REG (x
)) == to_mode
)
324 return SUBREG_REG (x
);
328 temp
= gen_rtx_LABEL_REF (to_mode
, label_ref_label (x
));
329 LABEL_REF_NONLOCAL_P (temp
) = LABEL_REF_NONLOCAL_P (x
);
333 temp
= shallow_copy_rtx (x
);
334 PUT_MODE (temp
, to_mode
);
338 temp
= convert_memory_address_addr_space_1 (to_mode
, XEXP (x
, 0), as
,
340 return temp
? gen_rtx_CONST (to_mode
, temp
) : temp
;
344 /* For addition we can safely permute the conversion and addition
345 operation if one operand is a constant and converting the constant
346 does not change it or if one operand is a constant and we are
347 using a ptr_extend instruction (POINTERS_EXTEND_UNSIGNED < 0).
348 We can always safely permute them if we are making the address
349 narrower. Inside a CONST RTL, this is safe for both pointers
350 zero or sign extended as pointers cannot wrap. */
351 if (GET_MODE_SIZE (to_mode
) < GET_MODE_SIZE (from_mode
)
352 || (GET_CODE (x
) == PLUS
353 && CONST_INT_P (XEXP (x
, 1))
354 && ((in_const
&& POINTERS_EXTEND_UNSIGNED
!= 0)
355 || XEXP (x
, 1) == convert_memory_address_addr_space_1
356 (to_mode
, XEXP (x
, 1), as
, in_const
,
358 || POINTERS_EXTEND_UNSIGNED
< 0)))
360 temp
= convert_memory_address_addr_space_1 (to_mode
, XEXP (x
, 0),
361 as
, in_const
, no_emit
);
362 return (temp
? gen_rtx_fmt_ee (GET_CODE (x
), to_mode
,
375 return convert_modes (to_mode
, from_mode
,
376 x
, POINTERS_EXTEND_UNSIGNED
);
377 #endif /* defined(POINTERS_EXTEND_UNSIGNED) */
380 /* Given X, a memory address in address space AS' pointer mode, convert it to
381 an address in the address space's address mode, or vice versa (TO_MODE says
382 which way). We take advantage of the fact that pointers are not allowed to
383 overflow by commuting arithmetic operations over conversions so that address
384 arithmetic insns can be used. */
387 convert_memory_address_addr_space (scalar_int_mode to_mode
, rtx x
,
390 return convert_memory_address_addr_space_1 (to_mode
, x
, as
, false, false);
394 /* Return something equivalent to X but valid as a memory address for something
395 of mode MODE in the named address space AS. When X is not itself valid,
396 this works by copying X or subexpressions of it into registers. */
399 memory_address_addr_space (machine_mode mode
, rtx x
, addr_space_t as
)
402 scalar_int_mode address_mode
= targetm
.addr_space
.address_mode (as
);
404 x
= convert_memory_address_addr_space (address_mode
, x
, as
);
406 /* By passing constant addresses through registers
407 we get a chance to cse them. */
408 if (! cse_not_expected
&& CONSTANT_P (x
) && CONSTANT_ADDRESS_P (x
))
409 x
= force_reg (address_mode
, x
);
411 /* We get better cse by rejecting indirect addressing at this stage.
412 Let the combiner create indirect addresses where appropriate.
413 For now, generate the code so that the subexpressions useful to share
414 are visible. But not if cse won't be done! */
417 if (! cse_not_expected
&& !REG_P (x
))
418 x
= break_out_memory_refs (x
);
420 /* At this point, any valid address is accepted. */
421 if (memory_address_addr_space_p (mode
, x
, as
))
424 /* If it was valid before but breaking out memory refs invalidated it,
425 use it the old way. */
426 if (memory_address_addr_space_p (mode
, oldx
, as
))
432 /* Perform machine-dependent transformations on X
433 in certain cases. This is not necessary since the code
434 below can handle all possible cases, but machine-dependent
435 transformations can make better code. */
438 x
= targetm
.addr_space
.legitimize_address (x
, oldx
, mode
, as
);
439 if (orig_x
!= x
&& memory_address_addr_space_p (mode
, x
, as
))
443 /* PLUS and MULT can appear in special ways
444 as the result of attempts to make an address usable for indexing.
445 Usually they are dealt with by calling force_operand, below.
446 But a sum containing constant terms is special
447 if removing them makes the sum a valid address:
448 then we generate that address in a register
449 and index off of it. We do this because it often makes
450 shorter code, and because the addresses thus generated
451 in registers often become common subexpressions. */
452 if (GET_CODE (x
) == PLUS
)
454 rtx constant_term
= const0_rtx
;
455 rtx y
= eliminate_constant_term (x
, &constant_term
);
456 if (constant_term
== const0_rtx
457 || ! memory_address_addr_space_p (mode
, y
, as
))
458 x
= force_operand (x
, NULL_RTX
);
461 y
= gen_rtx_PLUS (GET_MODE (x
), copy_to_reg (y
), constant_term
);
462 if (! memory_address_addr_space_p (mode
, y
, as
))
463 x
= force_operand (x
, NULL_RTX
);
469 else if (GET_CODE (x
) == MULT
|| GET_CODE (x
) == MINUS
)
470 x
= force_operand (x
, NULL_RTX
);
472 /* If we have a register that's an invalid address,
473 it must be a hard reg of the wrong class. Copy it to a pseudo. */
477 /* Last resort: copy the value to a register, since
478 the register is a valid address. */
480 x
= force_reg (address_mode
, x
);
485 gcc_assert (memory_address_addr_space_p (mode
, x
, as
));
486 /* If we didn't change the address, we are done. Otherwise, mark
487 a reg as a pointer if we have REG or REG + CONST_INT. */
491 mark_reg_pointer (x
, BITS_PER_UNIT
);
492 else if (GET_CODE (x
) == PLUS
493 && REG_P (XEXP (x
, 0))
494 && CONST_INT_P (XEXP (x
, 1)))
495 mark_reg_pointer (XEXP (x
, 0), BITS_PER_UNIT
);
497 /* OLDX may have been the address on a temporary. Update the address
498 to indicate that X is now used. */
499 update_temp_slot_address (oldx
, x
);
504 /* Convert a mem ref into one with a valid memory address.
505 Pass through anything else unchanged. */
508 validize_mem (rtx ref
)
512 ref
= use_anchored_address (ref
);
513 if (memory_address_addr_space_p (GET_MODE (ref
), XEXP (ref
, 0),
514 MEM_ADDR_SPACE (ref
)))
517 /* Don't alter REF itself, since that is probably a stack slot. */
518 return replace_equiv_address (ref
, XEXP (ref
, 0));
521 /* If X is a memory reference to a member of an object block, try rewriting
522 it to use an anchor instead. Return the new memory reference on success
523 and the old one on failure. */
526 use_anchored_address (rtx x
)
529 HOST_WIDE_INT offset
;
532 if (!flag_section_anchors
)
538 /* Split the address into a base and offset. */
541 if (GET_CODE (base
) == CONST
542 && GET_CODE (XEXP (base
, 0)) == PLUS
543 && CONST_INT_P (XEXP (XEXP (base
, 0), 1)))
545 offset
+= INTVAL (XEXP (XEXP (base
, 0), 1));
546 base
= XEXP (XEXP (base
, 0), 0);
549 /* Check whether BASE is suitable for anchors. */
550 if (GET_CODE (base
) != SYMBOL_REF
551 || !SYMBOL_REF_HAS_BLOCK_INFO_P (base
)
552 || SYMBOL_REF_ANCHOR_P (base
)
553 || SYMBOL_REF_BLOCK (base
) == NULL
554 || !targetm
.use_anchors_for_symbol_p (base
))
557 /* Decide where BASE is going to be. */
558 place_block_symbol (base
);
560 /* Get the anchor we need to use. */
561 offset
+= SYMBOL_REF_BLOCK_OFFSET (base
);
562 base
= get_section_anchor (SYMBOL_REF_BLOCK (base
), offset
,
563 SYMBOL_REF_TLS_MODEL (base
));
565 /* Work out the offset from the anchor. */
566 offset
-= SYMBOL_REF_BLOCK_OFFSET (base
);
568 /* If we're going to run a CSE pass, force the anchor into a register.
569 We will then be able to reuse registers for several accesses, if the
570 target costs say that that's worthwhile. */
571 mode
= GET_MODE (base
);
572 if (!cse_not_expected
)
573 base
= force_reg (mode
, base
);
575 return replace_equiv_address (x
, plus_constant (mode
, base
, offset
));
578 /* Copy the value or contents of X to a new temp reg and return that reg. */
583 rtx temp
= gen_reg_rtx (GET_MODE (x
));
585 /* If not an operand, must be an address with PLUS and MULT so
586 do the computation. */
587 if (! general_operand (x
, VOIDmode
))
588 x
= force_operand (x
, temp
);
591 emit_move_insn (temp
, x
);
596 /* Like copy_to_reg but always give the new register mode Pmode
597 in case X is a constant. */
600 copy_addr_to_reg (rtx x
)
602 return copy_to_mode_reg (Pmode
, x
);
605 /* Like copy_to_reg but always give the new register mode MODE
606 in case X is a constant. */
609 copy_to_mode_reg (machine_mode mode
, rtx x
)
611 rtx temp
= gen_reg_rtx (mode
);
613 /* If not an operand, must be an address with PLUS and MULT so
614 do the computation. */
615 if (! general_operand (x
, VOIDmode
))
616 x
= force_operand (x
, temp
);
618 gcc_assert (GET_MODE (x
) == mode
|| GET_MODE (x
) == VOIDmode
);
620 emit_move_insn (temp
, x
);
624 /* Load X into a register if it is not already one.
625 Use mode MODE for the register.
626 X should be valid for mode MODE, but it may be a constant which
627 is valid for all integer modes; that's why caller must specify MODE.
629 The caller must not alter the value in the register we return,
630 since we mark it as a "constant" register. */
633 force_reg (machine_mode mode
, rtx x
)
641 if (general_operand (x
, mode
))
643 temp
= gen_reg_rtx (mode
);
644 insn
= emit_move_insn (temp
, x
);
648 temp
= force_operand (x
, NULL_RTX
);
650 insn
= get_last_insn ();
653 rtx temp2
= gen_reg_rtx (mode
);
654 insn
= emit_move_insn (temp2
, temp
);
659 /* Let optimizers know that TEMP's value never changes
660 and that X can be substituted for it. Don't get confused
661 if INSN set something else (such as a SUBREG of TEMP). */
663 && (set
= single_set (insn
)) != 0
664 && SET_DEST (set
) == temp
665 && ! rtx_equal_p (x
, SET_SRC (set
)))
666 set_unique_reg_note (insn
, REG_EQUAL
, x
);
668 /* Let optimizers know that TEMP is a pointer, and if so, the
669 known alignment of that pointer. */
672 if (GET_CODE (x
) == SYMBOL_REF
)
674 align
= BITS_PER_UNIT
;
675 if (SYMBOL_REF_DECL (x
) && DECL_P (SYMBOL_REF_DECL (x
)))
676 align
= DECL_ALIGN (SYMBOL_REF_DECL (x
));
678 else if (GET_CODE (x
) == LABEL_REF
)
679 align
= BITS_PER_UNIT
;
680 else if (GET_CODE (x
) == CONST
681 && GET_CODE (XEXP (x
, 0)) == PLUS
682 && GET_CODE (XEXP (XEXP (x
, 0), 0)) == SYMBOL_REF
683 && CONST_INT_P (XEXP (XEXP (x
, 0), 1)))
685 rtx s
= XEXP (XEXP (x
, 0), 0);
686 rtx c
= XEXP (XEXP (x
, 0), 1);
690 if (SYMBOL_REF_DECL (s
) && DECL_P (SYMBOL_REF_DECL (s
)))
691 sa
= DECL_ALIGN (SYMBOL_REF_DECL (s
));
697 ca
= ctz_hwi (INTVAL (c
)) * BITS_PER_UNIT
;
698 align
= MIN (sa
, ca
);
702 if (align
|| (MEM_P (x
) && MEM_POINTER (x
)))
703 mark_reg_pointer (temp
, align
);
709 /* If X is a memory ref, copy its contents to a new temp reg and return
710 that reg. Otherwise, return X. */
713 force_not_mem (rtx x
)
717 if (!MEM_P (x
) || GET_MODE (x
) == BLKmode
)
720 temp
= gen_reg_rtx (GET_MODE (x
));
723 REG_POINTER (temp
) = 1;
725 emit_move_insn (temp
, x
);
729 /* Copy X to TARGET (if it's nonzero and a reg)
730 or to a new temp reg and return that reg.
731 MODE is the mode to use for X in case it is a constant. */
734 copy_to_suggested_reg (rtx x
, rtx target
, machine_mode mode
)
738 if (target
&& REG_P (target
))
741 temp
= gen_reg_rtx (mode
);
743 emit_move_insn (temp
, x
);
747 /* Return the mode to use to pass or return a scalar of TYPE and MODE.
748 PUNSIGNEDP points to the signedness of the type and may be adjusted
749 to show what signedness to use on extension operations.
751 FOR_RETURN is nonzero if the caller is promoting the return value
752 of FNDECL, else it is for promoting args. */
755 promote_function_mode (const_tree type
, machine_mode mode
, int *punsignedp
,
756 const_tree funtype
, int for_return
)
758 /* Called without a type node for a libcall. */
759 if (type
== NULL_TREE
)
761 if (INTEGRAL_MODE_P (mode
))
762 return targetm
.calls
.promote_function_mode (NULL_TREE
, mode
,
769 switch (TREE_CODE (type
))
771 case INTEGER_TYPE
: case ENUMERAL_TYPE
: case BOOLEAN_TYPE
:
772 case REAL_TYPE
: case OFFSET_TYPE
: case FIXED_POINT_TYPE
:
773 case POINTER_TYPE
: case REFERENCE_TYPE
:
774 return targetm
.calls
.promote_function_mode (type
, mode
, punsignedp
, funtype
,
781 /* Return the mode to use to store a scalar of TYPE and MODE.
782 PUNSIGNEDP points to the signedness of the type and may be adjusted
783 to show what signedness to use on extension operations. */
786 promote_mode (const_tree type ATTRIBUTE_UNUSED
, machine_mode mode
,
787 int *punsignedp ATTRIBUTE_UNUSED
)
795 /* For libcalls this is invoked without TYPE from the backends
796 TARGET_PROMOTE_FUNCTION_MODE hooks. Don't do anything in that
798 if (type
== NULL_TREE
)
801 /* FIXME: this is the same logic that was there until GCC 4.4, but we
802 probably want to test POINTERS_EXTEND_UNSIGNED even if PROMOTE_MODE
803 is not defined. The affected targets are M32C, S390, SPARC. */
805 code
= TREE_CODE (type
);
806 unsignedp
= *punsignedp
;
810 case INTEGER_TYPE
: case ENUMERAL_TYPE
: case BOOLEAN_TYPE
:
811 case REAL_TYPE
: case OFFSET_TYPE
: case FIXED_POINT_TYPE
:
812 /* Values of these types always have scalar mode. */
813 smode
= as_a
<scalar_mode
> (mode
);
814 PROMOTE_MODE (smode
, unsignedp
, type
);
815 *punsignedp
= unsignedp
;
818 #ifdef POINTERS_EXTEND_UNSIGNED
821 *punsignedp
= POINTERS_EXTEND_UNSIGNED
;
822 return targetm
.addr_space
.address_mode
823 (TYPE_ADDR_SPACE (TREE_TYPE (type
)));
835 /* Use one of promote_mode or promote_function_mode to find the promoted
836 mode of DECL. If PUNSIGNEDP is not NULL, store there the unsignedness
837 of DECL after promotion. */
840 promote_decl_mode (const_tree decl
, int *punsignedp
)
842 tree type
= TREE_TYPE (decl
);
843 int unsignedp
= TYPE_UNSIGNED (type
);
844 machine_mode mode
= DECL_MODE (decl
);
847 if (TREE_CODE (decl
) == RESULT_DECL
&& !DECL_BY_REFERENCE (decl
))
848 pmode
= promote_function_mode (type
, mode
, &unsignedp
,
849 TREE_TYPE (current_function_decl
), 1);
850 else if (TREE_CODE (decl
) == RESULT_DECL
|| TREE_CODE (decl
) == PARM_DECL
)
851 pmode
= promote_function_mode (type
, mode
, &unsignedp
,
852 TREE_TYPE (current_function_decl
), 2);
854 pmode
= promote_mode (type
, mode
, &unsignedp
);
857 *punsignedp
= unsignedp
;
861 /* Return the promoted mode for name. If it is a named SSA_NAME, it
862 is the same as promote_decl_mode. Otherwise, it is the promoted
863 mode of a temp decl of same type as the SSA_NAME, if we had created
867 promote_ssa_mode (const_tree name
, int *punsignedp
)
869 gcc_assert (TREE_CODE (name
) == SSA_NAME
);
871 /* Partitions holding parms and results must be promoted as expected
873 if (SSA_NAME_VAR (name
)
874 && (TREE_CODE (SSA_NAME_VAR (name
)) == PARM_DECL
875 || TREE_CODE (SSA_NAME_VAR (name
)) == RESULT_DECL
))
877 machine_mode mode
= promote_decl_mode (SSA_NAME_VAR (name
), punsignedp
);
882 tree type
= TREE_TYPE (name
);
883 int unsignedp
= TYPE_UNSIGNED (type
);
884 machine_mode mode
= TYPE_MODE (type
);
886 /* Bypass TYPE_MODE when it maps vector modes to BLKmode. */
889 gcc_assert (VECTOR_TYPE_P (type
));
890 mode
= type
->type_common
.mode
;
893 machine_mode pmode
= promote_mode (type
, mode
, &unsignedp
);
895 *punsignedp
= unsignedp
;
902 /* Controls the behavior of {anti_,}adjust_stack. */
903 static bool suppress_reg_args_size
;
905 /* A helper for adjust_stack and anti_adjust_stack. */
908 adjust_stack_1 (rtx adjust
, bool anti_p
)
913 /* Hereafter anti_p means subtract_p. */
914 if (!STACK_GROWS_DOWNWARD
)
917 temp
= expand_binop (Pmode
,
918 anti_p
? sub_optab
: add_optab
,
919 stack_pointer_rtx
, adjust
, stack_pointer_rtx
, 0,
922 if (temp
!= stack_pointer_rtx
)
923 insn
= emit_move_insn (stack_pointer_rtx
, temp
);
926 insn
= get_last_insn ();
927 temp
= single_set (insn
);
928 gcc_assert (temp
!= NULL
&& SET_DEST (temp
) == stack_pointer_rtx
);
931 if (!suppress_reg_args_size
)
932 add_reg_note (insn
, REG_ARGS_SIZE
, GEN_INT (stack_pointer_delta
));
935 /* Adjust the stack pointer by ADJUST (an rtx for a number of bytes).
936 This pops when ADJUST is positive. ADJUST need not be constant. */
939 adjust_stack (rtx adjust
)
941 if (adjust
== const0_rtx
)
944 /* We expect all variable sized adjustments to be multiple of
945 PREFERRED_STACK_BOUNDARY. */
946 if (CONST_INT_P (adjust
))
947 stack_pointer_delta
-= INTVAL (adjust
);
949 adjust_stack_1 (adjust
, false);
952 /* Adjust the stack pointer by minus ADJUST (an rtx for a number of bytes).
953 This pushes when ADJUST is positive. ADJUST need not be constant. */
956 anti_adjust_stack (rtx adjust
)
958 if (adjust
== const0_rtx
)
961 /* We expect all variable sized adjustments to be multiple of
962 PREFERRED_STACK_BOUNDARY. */
963 if (CONST_INT_P (adjust
))
964 stack_pointer_delta
+= INTVAL (adjust
);
966 adjust_stack_1 (adjust
, true);
969 /* Round the size of a block to be pushed up to the boundary required
970 by this machine. SIZE is the desired size, which need not be constant. */
973 round_push (rtx size
)
975 rtx align_rtx
, alignm1_rtx
;
977 if (!SUPPORTS_STACK_ALIGNMENT
978 || crtl
->preferred_stack_boundary
== MAX_SUPPORTED_STACK_ALIGNMENT
)
980 int align
= crtl
->preferred_stack_boundary
/ BITS_PER_UNIT
;
985 if (CONST_INT_P (size
))
987 HOST_WIDE_INT new_size
= (INTVAL (size
) + align
- 1) / align
* align
;
989 if (INTVAL (size
) != new_size
)
990 size
= GEN_INT (new_size
);
994 align_rtx
= GEN_INT (align
);
995 alignm1_rtx
= GEN_INT (align
- 1);
999 /* If crtl->preferred_stack_boundary might still grow, use
1000 virtual_preferred_stack_boundary_rtx instead. This will be
1001 substituted by the right value in vregs pass and optimized
1003 align_rtx
= virtual_preferred_stack_boundary_rtx
;
1004 alignm1_rtx
= force_operand (plus_constant (Pmode
, align_rtx
, -1),
1008 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
1009 but we know it can't. So add ourselves and then do
1011 size
= expand_binop (Pmode
, add_optab
, size
, alignm1_rtx
,
1012 NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
1013 size
= expand_divmod (0, TRUNC_DIV_EXPR
, Pmode
, size
, align_rtx
,
1015 size
= expand_mult (Pmode
, size
, align_rtx
, NULL_RTX
, 1);
1020 /* Save the stack pointer for the purpose in SAVE_LEVEL. PSAVE is a pointer
1021 to a previously-created save area. If no save area has been allocated,
1022 this function will allocate one. If a save area is specified, it
1023 must be of the proper mode. */
1026 emit_stack_save (enum save_level save_level
, rtx
*psave
)
1029 /* The default is that we use a move insn and save in a Pmode object. */
1030 rtx_insn
*(*fcn
) (rtx
, rtx
) = gen_move_insn
;
1031 machine_mode mode
= STACK_SAVEAREA_MODE (save_level
);
1033 /* See if this machine has anything special to do for this kind of save. */
1037 if (targetm
.have_save_stack_block ())
1038 fcn
= targetm
.gen_save_stack_block
;
1041 if (targetm
.have_save_stack_function ())
1042 fcn
= targetm
.gen_save_stack_function
;
1045 if (targetm
.have_save_stack_nonlocal ())
1046 fcn
= targetm
.gen_save_stack_nonlocal
;
1052 /* If there is no save area and we have to allocate one, do so. Otherwise
1053 verify the save area is the proper mode. */
1057 if (mode
!= VOIDmode
)
1059 if (save_level
== SAVE_NONLOCAL
)
1060 *psave
= sa
= assign_stack_local (mode
, GET_MODE_SIZE (mode
), 0);
1062 *psave
= sa
= gen_reg_rtx (mode
);
1066 do_pending_stack_adjust ();
1068 sa
= validize_mem (sa
);
1069 emit_insn (fcn (sa
, stack_pointer_rtx
));
1072 /* Restore the stack pointer for the purpose in SAVE_LEVEL. SA is the save
1073 area made by emit_stack_save. If it is zero, we have nothing to do. */
1076 emit_stack_restore (enum save_level save_level
, rtx sa
)
1078 /* The default is that we use a move insn. */
1079 rtx_insn
*(*fcn
) (rtx
, rtx
) = gen_move_insn
;
1081 /* If stack_realign_drap, the x86 backend emits a prologue that aligns both
1082 STACK_POINTER and HARD_FRAME_POINTER.
1083 If stack_realign_fp, the x86 backend emits a prologue that aligns only
1084 STACK_POINTER. This renders the HARD_FRAME_POINTER unusable for accessing
1085 aligned variables, which is reflected in ix86_can_eliminate.
1086 We normally still have the realigned STACK_POINTER that we can use.
1087 But if there is a stack restore still present at reload, it can trigger
1088 mark_not_eliminable for the STACK_POINTER, leaving no way to eliminate
1089 FRAME_POINTER into a hard reg.
1090 To prevent this situation, we force need_drap if we emit a stack
1092 if (SUPPORTS_STACK_ALIGNMENT
)
1093 crtl
->need_drap
= true;
1095 /* See if this machine has anything special to do for this kind of save. */
1099 if (targetm
.have_restore_stack_block ())
1100 fcn
= targetm
.gen_restore_stack_block
;
1103 if (targetm
.have_restore_stack_function ())
1104 fcn
= targetm
.gen_restore_stack_function
;
1107 if (targetm
.have_restore_stack_nonlocal ())
1108 fcn
= targetm
.gen_restore_stack_nonlocal
;
1116 sa
= validize_mem (sa
);
1117 /* These clobbers prevent the scheduler from moving
1118 references to variable arrays below the code
1119 that deletes (pops) the arrays. */
1120 emit_clobber (gen_rtx_MEM (BLKmode
, gen_rtx_SCRATCH (VOIDmode
)));
1121 emit_clobber (gen_rtx_MEM (BLKmode
, stack_pointer_rtx
));
1124 discard_pending_stack_adjust ();
1126 emit_insn (fcn (stack_pointer_rtx
, sa
));
1129 /* Invoke emit_stack_save on the nonlocal_goto_save_area for the current
1130 function. This should be called whenever we allocate or deallocate
1131 dynamic stack space. */
1134 update_nonlocal_goto_save_area (void)
1139 /* The nonlocal_goto_save_area object is an array of N pointers. The
1140 first one is used for the frame pointer save; the rest are sized by
1141 STACK_SAVEAREA_MODE. Create a reference to array index 1, the first
1142 of the stack save area slots. */
1143 t_save
= build4 (ARRAY_REF
,
1144 TREE_TYPE (TREE_TYPE (cfun
->nonlocal_goto_save_area
)),
1145 cfun
->nonlocal_goto_save_area
,
1146 integer_one_node
, NULL_TREE
, NULL_TREE
);
1147 r_save
= expand_expr (t_save
, NULL_RTX
, VOIDmode
, EXPAND_WRITE
);
1149 emit_stack_save (SAVE_NONLOCAL
, &r_save
);
1152 /* Record a new stack level for the current function. This should be called
1153 whenever we allocate or deallocate dynamic stack space. */
1156 record_new_stack_level (void)
1158 /* Record the new stack level for nonlocal gotos. */
1159 if (cfun
->nonlocal_goto_save_area
)
1160 update_nonlocal_goto_save_area ();
1162 /* Record the new stack level for SJLJ exceptions. */
1163 if (targetm_common
.except_unwind_info (&global_options
) == UI_SJLJ
)
1164 update_sjlj_context ();
1167 /* Return an rtx doing runtime alignment to REQUIRED_ALIGN on TARGET. */
1169 align_dynamic_address (rtx target
, unsigned required_align
)
1171 /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
1172 but we know it can't. So add ourselves and then do
1174 target
= expand_binop (Pmode
, add_optab
, target
,
1175 gen_int_mode (required_align
/ BITS_PER_UNIT
- 1,
1177 NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
1178 target
= expand_divmod (0, TRUNC_DIV_EXPR
, Pmode
, target
,
1179 gen_int_mode (required_align
/ BITS_PER_UNIT
,
1182 target
= expand_mult (Pmode
, target
,
1183 gen_int_mode (required_align
/ BITS_PER_UNIT
,
1190 /* Return an rtx through *PSIZE, representing the size of an area of memory to
1191 be dynamically pushed on the stack.
1193 *PSIZE is an rtx representing the size of the area.
1195 SIZE_ALIGN is the alignment (in bits) that we know SIZE has. This
1196 parameter may be zero. If so, a proper value will be extracted
1197 from SIZE if it is constant, otherwise BITS_PER_UNIT will be assumed.
1199 REQUIRED_ALIGN is the alignment (in bits) required for the region
1202 If PSTACK_USAGE_SIZE is not NULL it points to a value that is increased for
1203 the additional size returned. */
1205 get_dynamic_stack_size (rtx
*psize
, unsigned size_align
,
1206 unsigned required_align
,
1207 HOST_WIDE_INT
*pstack_usage_size
)
1212 /* Ensure the size is in the proper mode. */
1213 if (GET_MODE (size
) != VOIDmode
&& GET_MODE (size
) != Pmode
)
1214 size
= convert_to_mode (Pmode
, size
, 1);
1216 if (CONST_INT_P (size
))
1218 unsigned HOST_WIDE_INT lsb
;
1220 lsb
= INTVAL (size
);
1223 /* Watch out for overflow truncating to "unsigned". */
1224 if (lsb
> UINT_MAX
/ BITS_PER_UNIT
)
1225 size_align
= 1u << (HOST_BITS_PER_INT
- 1);
1227 size_align
= (unsigned)lsb
* BITS_PER_UNIT
;
1229 else if (size_align
< BITS_PER_UNIT
)
1230 size_align
= BITS_PER_UNIT
;
1232 /* We can't attempt to minimize alignment necessary, because we don't
1233 know the final value of preferred_stack_boundary yet while executing
1235 if (crtl
->preferred_stack_boundary
< PREFERRED_STACK_BOUNDARY
)
1236 crtl
->preferred_stack_boundary
= PREFERRED_STACK_BOUNDARY
;
1238 /* We will need to ensure that the address we return is aligned to
1239 REQUIRED_ALIGN. At this point in the compilation, we don't always
1240 know the final value of the STACK_DYNAMIC_OFFSET used in function.c
1241 (it might depend on the size of the outgoing parameter lists, for
1242 example), so we must preventively align the value. We leave space
1243 in SIZE for the hole that might result from the alignment operation. */
1245 /* Since the stack is presumed to be aligned before this allocation,
1246 we only need to increase the size of the allocation if the required
1247 alignment is more than the stack alignment. */
1248 if (required_align
> STACK_BOUNDARY
)
1250 extra
= (required_align
- STACK_BOUNDARY
) / BITS_PER_UNIT
;
1251 size
= plus_constant (Pmode
, size
, extra
);
1252 size
= force_operand (size
, NULL_RTX
);
1253 if (size_align
> STACK_BOUNDARY
)
1254 size_align
= STACK_BOUNDARY
;
1256 if (flag_stack_usage_info
&& pstack_usage_size
)
1257 *pstack_usage_size
+= extra
;
1260 /* Round the size to a multiple of the required stack alignment.
1261 Since the stack is presumed to be rounded before this allocation,
1262 this will maintain the required alignment.
1264 If the stack grows downward, we could save an insn by subtracting
1265 SIZE from the stack pointer and then aligning the stack pointer.
1266 The problem with this is that the stack pointer may be unaligned
1267 between the execution of the subtraction and alignment insns and
1268 some machines do not allow this. Even on those that do, some
1269 signal handlers malfunction if a signal should occur between those
1270 insns. Since this is an extremely rare event, we have no reliable
1271 way of knowing which systems have this problem. So we avoid even
1272 momentarily mis-aligning the stack. */
1273 if (size_align
% MAX_SUPPORTED_STACK_ALIGNMENT
!= 0)
1275 size
= round_push (size
);
1277 if (flag_stack_usage_info
&& pstack_usage_size
)
1279 int align
= crtl
->preferred_stack_boundary
/ BITS_PER_UNIT
;
1280 *pstack_usage_size
=
1281 (*pstack_usage_size
+ align
- 1) / align
* align
;
1288 /* Return the number of bytes to "protect" on the stack for -fstack-check.
1290 "protect" in the context of -fstack-check means how many bytes we
1291 should always ensure are available on the stack. More importantly
1292 this is how many bytes are skipped when probing the stack.
1294 On some targets we want to reuse the -fstack-check prologue support
1295 to give a degree of protection against stack clashing style attacks.
1297 In that scenario we do not want to skip bytes before probing as that
1298 would render the stack clash protections useless.
1300 So we never use STACK_CHECK_PROTECT directly. Instead we indirect though
1301 this helper which allows us to provide different values for
1302 -fstack-check and -fstack-clash-protection. */
1304 get_stack_check_protect (void)
1306 if (flag_stack_clash_protection
)
1308 return STACK_CHECK_PROTECT
;
1311 /* Return an rtx representing the address of an area of memory dynamically
1312 pushed on the stack.
1314 Any required stack pointer alignment is preserved.
1316 SIZE is an rtx representing the size of the area.
1318 SIZE_ALIGN is the alignment (in bits) that we know SIZE has. This
1319 parameter may be zero. If so, a proper value will be extracted
1320 from SIZE if it is constant, otherwise BITS_PER_UNIT will be assumed.
1322 REQUIRED_ALIGN is the alignment (in bits) required for the region
1325 If CANNOT_ACCUMULATE is set to TRUE, the caller guarantees that the
1326 stack space allocated by the generated code cannot be added with itself
1327 in the course of the execution of the function. It is always safe to
1328 pass FALSE here and the following criterion is sufficient in order to
1329 pass TRUE: every path in the CFG that starts at the allocation point and
1330 loops to it executes the associated deallocation code. */
1333 allocate_dynamic_stack_space (rtx size
, unsigned size_align
,
1334 unsigned required_align
, bool cannot_accumulate
)
1336 HOST_WIDE_INT stack_usage_size
= -1;
1337 rtx_code_label
*final_label
;
1338 rtx final_target
, target
;
1340 /* If we're asking for zero bytes, it doesn't matter what we point
1341 to since we can't dereference it. But return a reasonable
1343 if (size
== const0_rtx
)
1344 return virtual_stack_dynamic_rtx
;
1346 /* Otherwise, show we're calling alloca or equivalent. */
1347 cfun
->calls_alloca
= 1;
1349 /* If stack usage info is requested, look into the size we are passed.
1350 We need to do so this early to avoid the obfuscation that may be
1351 introduced later by the various alignment operations. */
1352 if (flag_stack_usage_info
)
1354 if (CONST_INT_P (size
))
1355 stack_usage_size
= INTVAL (size
);
1356 else if (REG_P (size
))
1358 /* Look into the last emitted insn and see if we can deduce
1359 something for the register. */
1362 insn
= get_last_insn ();
1363 if ((set
= single_set (insn
)) && rtx_equal_p (SET_DEST (set
), size
))
1365 if (CONST_INT_P (SET_SRC (set
)))
1366 stack_usage_size
= INTVAL (SET_SRC (set
));
1367 else if ((note
= find_reg_equal_equiv_note (insn
))
1368 && CONST_INT_P (XEXP (note
, 0)))
1369 stack_usage_size
= INTVAL (XEXP (note
, 0));
1373 /* If the size is not constant, we can't say anything. */
1374 if (stack_usage_size
== -1)
1376 current_function_has_unbounded_dynamic_stack_size
= 1;
1377 stack_usage_size
= 0;
1381 get_dynamic_stack_size (&size
, size_align
, required_align
, &stack_usage_size
);
1383 target
= gen_reg_rtx (Pmode
);
1385 /* The size is supposed to be fully adjusted at this point so record it
1386 if stack usage info is requested. */
1387 if (flag_stack_usage_info
)
1389 current_function_dynamic_stack_size
+= stack_usage_size
;
1391 /* ??? This is gross but the only safe stance in the absence
1392 of stack usage oriented flow analysis. */
1393 if (!cannot_accumulate
)
1394 current_function_has_unbounded_dynamic_stack_size
= 1;
1397 do_pending_stack_adjust ();
1400 final_target
= NULL_RTX
;
1402 /* If we are splitting the stack, we need to ask the backend whether
1403 there is enough room on the current stack. If there isn't, or if
1404 the backend doesn't know how to tell is, then we need to call a
1405 function to allocate memory in some other way. This memory will
1406 be released when we release the current stack segment. The
1407 effect is that stack allocation becomes less efficient, but at
1408 least it doesn't cause a stack overflow. */
1409 if (flag_split_stack
)
1411 rtx_code_label
*available_label
;
1412 rtx ask
, space
, func
;
1414 available_label
= NULL
;
1416 if (targetm
.have_split_stack_space_check ())
1418 available_label
= gen_label_rtx ();
1420 /* This instruction will branch to AVAILABLE_LABEL if there
1421 are SIZE bytes available on the stack. */
1422 emit_insn (targetm
.gen_split_stack_space_check
1423 (size
, available_label
));
1426 /* The __morestack_allocate_stack_space function will allocate
1427 memory using malloc. If the alignment of the memory returned
1428 by malloc does not meet REQUIRED_ALIGN, we increase SIZE to
1429 make sure we allocate enough space. */
1430 if (MALLOC_ABI_ALIGNMENT
>= required_align
)
1433 ask
= expand_binop (Pmode
, add_optab
, size
,
1434 gen_int_mode (required_align
/ BITS_PER_UNIT
- 1,
1436 NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
1438 func
= init_one_libfunc ("__morestack_allocate_stack_space");
1440 space
= emit_library_call_value (func
, target
, LCT_NORMAL
, Pmode
,
1443 if (available_label
== NULL_RTX
)
1446 final_target
= gen_reg_rtx (Pmode
);
1448 emit_move_insn (final_target
, space
);
1450 final_label
= gen_label_rtx ();
1451 emit_jump (final_label
);
1453 emit_label (available_label
);
1456 /* We ought to be called always on the toplevel and stack ought to be aligned
1458 gcc_assert (!(stack_pointer_delta
1459 % (PREFERRED_STACK_BOUNDARY
/ BITS_PER_UNIT
)));
1461 /* If needed, check that we have the required amount of stack. Take into
1462 account what has already been checked. */
1463 if (STACK_CHECK_MOVING_SP
)
1465 else if (flag_stack_check
== GENERIC_STACK_CHECK
)
1466 probe_stack_range (STACK_OLD_CHECK_PROTECT
+ STACK_CHECK_MAX_FRAME_SIZE
,
1468 else if (flag_stack_check
== STATIC_BUILTIN_STACK_CHECK
)
1469 probe_stack_range (get_stack_check_protect (), size
);
1471 /* Don't let anti_adjust_stack emit notes. */
1472 suppress_reg_args_size
= true;
1474 /* Perform the required allocation from the stack. Some systems do
1475 this differently than simply incrementing/decrementing from the
1476 stack pointer, such as acquiring the space by calling malloc(). */
1477 if (targetm
.have_allocate_stack ())
1479 struct expand_operand ops
[2];
1480 /* We don't have to check against the predicate for operand 0 since
1481 TARGET is known to be a pseudo of the proper mode, which must
1482 be valid for the operand. */
1483 create_fixed_operand (&ops
[0], target
);
1484 create_convert_operand_to (&ops
[1], size
, STACK_SIZE_MODE
, true);
1485 expand_insn (targetm
.code_for_allocate_stack
, 2, ops
);
1489 int saved_stack_pointer_delta
;
1491 if (!STACK_GROWS_DOWNWARD
)
1492 emit_move_insn (target
, virtual_stack_dynamic_rtx
);
1494 /* Check stack bounds if necessary. */
1495 if (crtl
->limit_stack
)
1498 rtx_code_label
*space_available
= gen_label_rtx ();
1499 if (STACK_GROWS_DOWNWARD
)
1500 available
= expand_binop (Pmode
, sub_optab
,
1501 stack_pointer_rtx
, stack_limit_rtx
,
1502 NULL_RTX
, 1, OPTAB_WIDEN
);
1504 available
= expand_binop (Pmode
, sub_optab
,
1505 stack_limit_rtx
, stack_pointer_rtx
,
1506 NULL_RTX
, 1, OPTAB_WIDEN
);
1508 emit_cmp_and_jump_insns (available
, size
, GEU
, NULL_RTX
, Pmode
, 1,
1510 if (targetm
.have_trap ())
1511 emit_insn (targetm
.gen_trap ());
1513 error ("stack limits not supported on this target");
1515 emit_label (space_available
);
1518 saved_stack_pointer_delta
= stack_pointer_delta
;
1520 if (flag_stack_check
&& STACK_CHECK_MOVING_SP
)
1521 anti_adjust_stack_and_probe (size
, false);
1522 else if (flag_stack_clash_protection
)
1523 anti_adjust_stack_and_probe_stack_clash (size
);
1525 anti_adjust_stack (size
);
1527 /* Even if size is constant, don't modify stack_pointer_delta.
1528 The constant size alloca should preserve
1529 crtl->preferred_stack_boundary alignment. */
1530 stack_pointer_delta
= saved_stack_pointer_delta
;
1532 if (STACK_GROWS_DOWNWARD
)
1533 emit_move_insn (target
, virtual_stack_dynamic_rtx
);
1536 suppress_reg_args_size
= false;
1538 /* Finish up the split stack handling. */
1539 if (final_label
!= NULL_RTX
)
1541 gcc_assert (flag_split_stack
);
1542 emit_move_insn (final_target
, target
);
1543 emit_label (final_label
);
1544 target
= final_target
;
1547 target
= align_dynamic_address (target
, required_align
);
1549 /* Now that we've committed to a return value, mark its alignment. */
1550 mark_reg_pointer (target
, required_align
);
1552 /* Record the new stack level. */
1553 record_new_stack_level ();
1558 /* Return an rtx representing the address of an area of memory already
1559 statically pushed onto the stack in the virtual stack vars area. (It is
1560 assumed that the area is allocated in the function prologue.)
1562 Any required stack pointer alignment is preserved.
1564 OFFSET is the offset of the area into the virtual stack vars area.
1566 REQUIRED_ALIGN is the alignment (in bits) required for the region
1570 get_dynamic_stack_base (HOST_WIDE_INT offset
, unsigned required_align
)
1574 if (crtl
->preferred_stack_boundary
< PREFERRED_STACK_BOUNDARY
)
1575 crtl
->preferred_stack_boundary
= PREFERRED_STACK_BOUNDARY
;
1577 target
= gen_reg_rtx (Pmode
);
1578 emit_move_insn (target
, virtual_stack_vars_rtx
);
1579 target
= expand_binop (Pmode
, add_optab
, target
,
1580 gen_int_mode (offset
, Pmode
),
1581 NULL_RTX
, 1, OPTAB_LIB_WIDEN
);
1582 target
= align_dynamic_address (target
, required_align
);
1584 /* Now that we've committed to a return value, mark its alignment. */
1585 mark_reg_pointer (target
, required_align
);
1590 /* A front end may want to override GCC's stack checking by providing a
1591 run-time routine to call to check the stack, so provide a mechanism for
1592 calling that routine. */
1594 static GTY(()) rtx stack_check_libfunc
;
1597 set_stack_check_libfunc (const char *libfunc_name
)
1599 gcc_assert (stack_check_libfunc
== NULL_RTX
);
1600 stack_check_libfunc
= gen_rtx_SYMBOL_REF (Pmode
, libfunc_name
);
1603 /* Emit one stack probe at ADDRESS, an address within the stack. */
1606 emit_stack_probe (rtx address
)
1608 if (targetm
.have_probe_stack_address ())
1609 emit_insn (targetm
.gen_probe_stack_address (address
));
1612 rtx memref
= gen_rtx_MEM (word_mode
, address
);
1614 MEM_VOLATILE_P (memref
) = 1;
1616 /* See if we have an insn to probe the stack. */
1617 if (targetm
.have_probe_stack ())
1618 emit_insn (targetm
.gen_probe_stack (memref
));
1620 emit_move_insn (memref
, const0_rtx
);
1624 /* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
1625 FIRST is a constant and size is a Pmode RTX. These are offsets from
1626 the current stack pointer. STACK_GROWS_DOWNWARD says whether to add
1627 or subtract them from the stack pointer. */
1629 #define PROBE_INTERVAL (1 << STACK_CHECK_PROBE_INTERVAL_EXP)
1631 #if STACK_GROWS_DOWNWARD
1632 #define STACK_GROW_OP MINUS
1633 #define STACK_GROW_OPTAB sub_optab
1634 #define STACK_GROW_OFF(off) -(off)
1636 #define STACK_GROW_OP PLUS
1637 #define STACK_GROW_OPTAB add_optab
1638 #define STACK_GROW_OFF(off) (off)
1642 probe_stack_range (HOST_WIDE_INT first
, rtx size
)
1644 /* First ensure SIZE is Pmode. */
1645 if (GET_MODE (size
) != VOIDmode
&& GET_MODE (size
) != Pmode
)
1646 size
= convert_to_mode (Pmode
, size
, 1);
1648 /* Next see if we have a function to check the stack. */
1649 if (stack_check_libfunc
)
1651 rtx addr
= memory_address (Pmode
,
1652 gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1654 plus_constant (Pmode
,
1656 emit_library_call (stack_check_libfunc
, LCT_THROW
, VOIDmode
,
1660 /* Next see if we have an insn to check the stack. */
1661 else if (targetm
.have_check_stack ())
1663 struct expand_operand ops
[1];
1664 rtx addr
= memory_address (Pmode
,
1665 gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1667 plus_constant (Pmode
,
1670 create_input_operand (&ops
[0], addr
, Pmode
);
1671 success
= maybe_expand_insn (targetm
.code_for_check_stack
, 1, ops
);
1672 gcc_assert (success
);
1675 /* Otherwise we have to generate explicit probes. If we have a constant
1676 small number of them to generate, that's the easy case. */
1677 else if (CONST_INT_P (size
) && INTVAL (size
) < 7 * PROBE_INTERVAL
)
1679 HOST_WIDE_INT isize
= INTVAL (size
), i
;
1682 /* Probe at FIRST + N * PROBE_INTERVAL for values of N from 1 until
1683 it exceeds SIZE. If only one probe is needed, this will not
1684 generate any code. Then probe at FIRST + SIZE. */
1685 for (i
= PROBE_INTERVAL
; i
< isize
; i
+= PROBE_INTERVAL
)
1687 addr
= memory_address (Pmode
,
1688 plus_constant (Pmode
, stack_pointer_rtx
,
1689 STACK_GROW_OFF (first
+ i
)));
1690 emit_stack_probe (addr
);
1693 addr
= memory_address (Pmode
,
1694 plus_constant (Pmode
, stack_pointer_rtx
,
1695 STACK_GROW_OFF (first
+ isize
)));
1696 emit_stack_probe (addr
);
1699 /* In the variable case, do the same as above, but in a loop. Note that we
1700 must be extra careful with variables wrapping around because we might be
1701 at the very top (or the very bottom) of the address space and we have to
1702 be able to handle this case properly; in particular, we use an equality
1703 test for the loop condition. */
1706 rtx rounded_size
, rounded_size_op
, test_addr
, last_addr
, temp
;
1707 rtx_code_label
*loop_lab
= gen_label_rtx ();
1708 rtx_code_label
*end_lab
= gen_label_rtx ();
1710 /* Step 1: round SIZE to the previous multiple of the interval. */
1712 /* ROUNDED_SIZE = SIZE & -PROBE_INTERVAL */
1714 = simplify_gen_binary (AND
, Pmode
, size
,
1715 gen_int_mode (-PROBE_INTERVAL
, Pmode
));
1716 rounded_size_op
= force_operand (rounded_size
, NULL_RTX
);
1719 /* Step 2: compute initial and final value of the loop counter. */
1721 /* TEST_ADDR = SP + FIRST. */
1722 test_addr
= force_operand (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1724 gen_int_mode (first
, Pmode
)),
1727 /* LAST_ADDR = SP + FIRST + ROUNDED_SIZE. */
1728 last_addr
= force_operand (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1730 rounded_size_op
), NULL_RTX
);
1735 while (TEST_ADDR != LAST_ADDR)
1737 TEST_ADDR = TEST_ADDR + PROBE_INTERVAL
1741 probes at FIRST + N * PROBE_INTERVAL for values of N from 1
1742 until it is equal to ROUNDED_SIZE. */
1744 emit_label (loop_lab
);
1746 /* Jump to END_LAB if TEST_ADDR == LAST_ADDR. */
1747 emit_cmp_and_jump_insns (test_addr
, last_addr
, EQ
, NULL_RTX
, Pmode
, 1,
1750 /* TEST_ADDR = TEST_ADDR + PROBE_INTERVAL. */
1751 temp
= expand_binop (Pmode
, STACK_GROW_OPTAB
, test_addr
,
1752 gen_int_mode (PROBE_INTERVAL
, Pmode
), test_addr
,
1755 gcc_assert (temp
== test_addr
);
1757 /* Probe at TEST_ADDR. */
1758 emit_stack_probe (test_addr
);
1760 emit_jump (loop_lab
);
1762 emit_label (end_lab
);
1765 /* Step 4: probe at FIRST + SIZE if we cannot assert at compile-time
1766 that SIZE is equal to ROUNDED_SIZE. */
1768 /* TEMP = SIZE - ROUNDED_SIZE. */
1769 temp
= simplify_gen_binary (MINUS
, Pmode
, size
, rounded_size
);
1770 if (temp
!= const0_rtx
)
1774 if (CONST_INT_P (temp
))
1776 /* Use [base + disp} addressing mode if supported. */
1777 HOST_WIDE_INT offset
= INTVAL (temp
);
1778 addr
= memory_address (Pmode
,
1779 plus_constant (Pmode
, last_addr
,
1780 STACK_GROW_OFF (offset
)));
1784 /* Manual CSE if the difference is not known at compile-time. */
1785 temp
= gen_rtx_MINUS (Pmode
, size
, rounded_size_op
);
1786 addr
= memory_address (Pmode
,
1787 gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1791 emit_stack_probe (addr
);
1795 /* Make sure nothing is scheduled before we are done. */
1796 emit_insn (gen_blockage ());
1799 /* Compute parameters for stack clash probing a dynamic stack
1800 allocation of SIZE bytes.
1802 We compute ROUNDED_SIZE, LAST_ADDR, RESIDUAL and PROBE_INTERVAL.
1804 Additionally we conditionally dump the type of probing that will
1805 be needed given the values computed. */
1808 compute_stack_clash_protection_loop_data (rtx
*rounded_size
, rtx
*last_addr
,
1810 HOST_WIDE_INT
*probe_interval
,
1813 /* Round SIZE down to STACK_CLASH_PROTECTION_PROBE_INTERVAL */
1815 = 1 << PARAM_VALUE (PARAM_STACK_CLASH_PROTECTION_PROBE_INTERVAL
);
1816 *rounded_size
= simplify_gen_binary (AND
, Pmode
, size
,
1817 GEN_INT (-*probe_interval
));
1819 /* Compute the value of the stack pointer for the last iteration.
1820 It's just SP + ROUNDED_SIZE. */
1821 rtx rounded_size_op
= force_operand (*rounded_size
, NULL_RTX
);
1822 *last_addr
= force_operand (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
1827 /* Compute any residuals not allocated by the loop above. Residuals
1828 are just the ROUNDED_SIZE - SIZE. */
1829 *residual
= simplify_gen_binary (MINUS
, Pmode
, size
, *rounded_size
);
1831 /* Dump key information to make writing tests easy. */
1834 if (*rounded_size
== CONST0_RTX (Pmode
))
1836 "Stack clash skipped dynamic allocation and probing loop.\n");
1837 else if (GET_CODE (*rounded_size
) == CONST_INT
1838 && INTVAL (*rounded_size
) <= 4 * *probe_interval
)
1840 "Stack clash dynamic allocation and probing inline.\n");
1841 else if (GET_CODE (*rounded_size
) == CONST_INT
)
1843 "Stack clash dynamic allocation and probing in "
1847 "Stack clash dynamic allocation and probing in loop.\n");
1849 if (*residual
!= CONST0_RTX (Pmode
))
1851 "Stack clash dynamic allocation and probing residuals.\n");
1854 "Stack clash skipped dynamic allocation and "
1855 "probing residuals.\n");
1859 /* Emit the start of an allocate/probe loop for stack
1862 LOOP_LAB and END_LAB are returned for use when we emit the
1865 LAST addr is the value for SP which stops the loop. */
1867 emit_stack_clash_protection_probe_loop_start (rtx
*loop_lab
,
1872 /* Essentially we want to emit any setup code, the top of loop
1873 label and the comparison at the top of the loop. */
1874 *loop_lab
= gen_label_rtx ();
1875 *end_lab
= gen_label_rtx ();
1877 emit_label (*loop_lab
);
1879 emit_cmp_and_jump_insns (stack_pointer_rtx
, last_addr
, EQ
, NULL_RTX
,
1880 Pmode
, 1, *end_lab
);
1883 /* Emit the end of a stack clash probing loop.
1885 This consists of just the jump back to LOOP_LAB and
1886 emitting END_LOOP after the loop. */
1889 emit_stack_clash_protection_probe_loop_end (rtx loop_lab
, rtx end_loop
,
1890 rtx last_addr
, bool rotated
)
1893 emit_cmp_and_jump_insns (stack_pointer_rtx
, last_addr
, NE
, NULL_RTX
,
1894 Pmode
, 1, loop_lab
);
1896 emit_jump (loop_lab
);
1898 emit_label (end_loop
);
1902 /* Adjust the stack pointer by minus SIZE (an rtx for a number of bytes)
1903 while probing it. This pushes when SIZE is positive. SIZE need not
1906 This is subtly different than anti_adjust_stack_and_probe to try and
1907 prevent stack-clash attacks
1909 1. It must assume no knowledge of the probing state, any allocation
1912 Consider the case of a 1 byte alloca in a loop. If the sum of the
1913 allocations is large, then this could be used to jump the guard if
1914 probes were not emitted.
1916 2. It never skips probes, whereas anti_adjust_stack_and_probe will
1917 skip probes on the first couple PROBE_INTERVALs on the assumption
1918 they're done elsewhere.
1920 3. It only allocates and probes SIZE bytes, it does not need to
1921 allocate/probe beyond that because this probing style does not
1922 guarantee signal handling capability if the guard is hit. */
1925 anti_adjust_stack_and_probe_stack_clash (rtx size
)
1927 /* First ensure SIZE is Pmode. */
1928 if (GET_MODE (size
) != VOIDmode
&& GET_MODE (size
) != Pmode
)
1929 size
= convert_to_mode (Pmode
, size
, 1);
1931 /* We can get here with a constant size on some targets. */
1932 rtx rounded_size
, last_addr
, residual
;
1933 HOST_WIDE_INT probe_interval
;
1934 compute_stack_clash_protection_loop_data (&rounded_size
, &last_addr
,
1935 &residual
, &probe_interval
, size
);
1937 if (rounded_size
!= CONST0_RTX (Pmode
))
1939 if (INTVAL (rounded_size
) <= 4 * probe_interval
)
1941 for (HOST_WIDE_INT i
= 0;
1942 i
< INTVAL (rounded_size
);
1943 i
+= probe_interval
)
1945 anti_adjust_stack (GEN_INT (probe_interval
));
1947 /* The prologue does not probe residuals. Thus the offset
1948 here to probe just beyond what the prologue had already
1950 emit_stack_probe (plus_constant (Pmode
, stack_pointer_rtx
,
1952 - GET_MODE_SIZE (word_mode
))));
1953 emit_insn (gen_blockage ());
1958 rtx loop_lab
, end_loop
;
1959 bool rotate_loop
= GET_CODE (rounded_size
) == CONST_INT
;
1960 emit_stack_clash_protection_probe_loop_start (&loop_lab
, &end_loop
,
1961 last_addr
, rotate_loop
);
1963 anti_adjust_stack (GEN_INT (probe_interval
));
1965 /* The prologue does not probe residuals. Thus the offset here
1966 to probe just beyond what the prologue had already allocated. */
1967 emit_stack_probe (plus_constant (Pmode
, stack_pointer_rtx
,
1969 - GET_MODE_SIZE (word_mode
))));
1971 emit_stack_clash_protection_probe_loop_end (loop_lab
, end_loop
,
1972 last_addr
, rotate_loop
);
1973 emit_insn (gen_blockage ());
1977 if (residual
!= CONST0_RTX (Pmode
))
1979 rtx x
= force_reg (Pmode
, plus_constant (Pmode
, residual
,
1980 -GET_MODE_SIZE (word_mode
)));
1981 anti_adjust_stack (residual
);
1982 emit_stack_probe (gen_rtx_PLUS (Pmode
, stack_pointer_rtx
, x
));
1983 emit_insn (gen_blockage ());
1986 /* Some targets make optimistic assumptions in their prologues about
1987 how the caller may have probed the stack. Make sure we honor
1988 those assumptions when needed. */
1989 if (size
!= CONST0_RTX (Pmode
)
1990 && targetm
.stack_clash_protection_final_dynamic_probe (residual
))
1992 /* Ideally we would just probe at *sp. However, if SIZE is not
1993 a compile-time constant, but is zero at runtime, then *sp
1994 might hold live data. So probe at *sp if we know that
1995 an allocation was made, otherwise probe into the red zone
1996 which is obviously undesirable. */
1997 if (GET_CODE (size
) == CONST_INT
)
1999 emit_stack_probe (stack_pointer_rtx
);
2000 emit_insn (gen_blockage ());
2004 emit_stack_probe (plus_constant (Pmode
, stack_pointer_rtx
,
2005 -GET_MODE_SIZE (word_mode
)));
2006 emit_insn (gen_blockage ());
2012 /* Adjust the stack pointer by minus SIZE (an rtx for a number of bytes)
2013 while probing it. This pushes when SIZE is positive. SIZE need not
2014 be constant. If ADJUST_BACK is true, adjust back the stack pointer
2015 by plus SIZE at the end. */
2018 anti_adjust_stack_and_probe (rtx size
, bool adjust_back
)
2020 /* We skip the probe for the first interval + a small dope of 4 words and
2021 probe that many bytes past the specified size to maintain a protection
2022 area at the botton of the stack. */
2023 const int dope
= 4 * UNITS_PER_WORD
;
2025 /* First ensure SIZE is Pmode. */
2026 if (GET_MODE (size
) != VOIDmode
&& GET_MODE (size
) != Pmode
)
2027 size
= convert_to_mode (Pmode
, size
, 1);
2029 /* If we have a constant small number of probes to generate, that's the
2031 if (CONST_INT_P (size
) && INTVAL (size
) < 7 * PROBE_INTERVAL
)
2033 HOST_WIDE_INT isize
= INTVAL (size
), i
;
2034 bool first_probe
= true;
2036 /* Adjust SP and probe at PROBE_INTERVAL + N * PROBE_INTERVAL for
2037 values of N from 1 until it exceeds SIZE. If only one probe is
2038 needed, this will not generate any code. Then adjust and probe
2039 to PROBE_INTERVAL + SIZE. */
2040 for (i
= PROBE_INTERVAL
; i
< isize
; i
+= PROBE_INTERVAL
)
2044 anti_adjust_stack (GEN_INT (2 * PROBE_INTERVAL
+ dope
));
2045 first_probe
= false;
2048 anti_adjust_stack (GEN_INT (PROBE_INTERVAL
));
2049 emit_stack_probe (stack_pointer_rtx
);
2053 anti_adjust_stack (plus_constant (Pmode
, size
, PROBE_INTERVAL
+ dope
));
2055 anti_adjust_stack (plus_constant (Pmode
, size
, PROBE_INTERVAL
- i
));
2056 emit_stack_probe (stack_pointer_rtx
);
2059 /* In the variable case, do the same as above, but in a loop. Note that we
2060 must be extra careful with variables wrapping around because we might be
2061 at the very top (or the very bottom) of the address space and we have to
2062 be able to handle this case properly; in particular, we use an equality
2063 test for the loop condition. */
2066 rtx rounded_size
, rounded_size_op
, last_addr
, temp
;
2067 rtx_code_label
*loop_lab
= gen_label_rtx ();
2068 rtx_code_label
*end_lab
= gen_label_rtx ();
2071 /* Step 1: round SIZE to the previous multiple of the interval. */
2073 /* ROUNDED_SIZE = SIZE & -PROBE_INTERVAL */
2075 = simplify_gen_binary (AND
, Pmode
, size
,
2076 gen_int_mode (-PROBE_INTERVAL
, Pmode
));
2077 rounded_size_op
= force_operand (rounded_size
, NULL_RTX
);
2080 /* Step 2: compute initial and final value of the loop counter. */
2082 /* SP = SP_0 + PROBE_INTERVAL. */
2083 anti_adjust_stack (GEN_INT (PROBE_INTERVAL
+ dope
));
2085 /* LAST_ADDR = SP_0 + PROBE_INTERVAL + ROUNDED_SIZE. */
2086 last_addr
= force_operand (gen_rtx_fmt_ee (STACK_GROW_OP
, Pmode
,
2088 rounded_size_op
), NULL_RTX
);
2093 while (SP != LAST_ADDR)
2095 SP = SP + PROBE_INTERVAL
2099 adjusts SP and probes at PROBE_INTERVAL + N * PROBE_INTERVAL for
2100 values of N from 1 until it is equal to ROUNDED_SIZE. */
2102 emit_label (loop_lab
);
2104 /* Jump to END_LAB if SP == LAST_ADDR. */
2105 emit_cmp_and_jump_insns (stack_pointer_rtx
, last_addr
, EQ
, NULL_RTX
,
2108 /* SP = SP + PROBE_INTERVAL and probe at SP. */
2109 anti_adjust_stack (GEN_INT (PROBE_INTERVAL
));
2110 emit_stack_probe (stack_pointer_rtx
);
2112 emit_jump (loop_lab
);
2114 emit_label (end_lab
);
2117 /* Step 4: adjust SP and probe at PROBE_INTERVAL + SIZE if we cannot
2118 assert at compile-time that SIZE is equal to ROUNDED_SIZE. */
2120 /* TEMP = SIZE - ROUNDED_SIZE. */
2121 temp
= simplify_gen_binary (MINUS
, Pmode
, size
, rounded_size
);
2122 if (temp
!= const0_rtx
)
2124 /* Manual CSE if the difference is not known at compile-time. */
2125 if (GET_CODE (temp
) != CONST_INT
)
2126 temp
= gen_rtx_MINUS (Pmode
, size
, rounded_size_op
);
2127 anti_adjust_stack (temp
);
2128 emit_stack_probe (stack_pointer_rtx
);
2132 /* Adjust back and account for the additional first interval. */
2134 adjust_stack (plus_constant (Pmode
, size
, PROBE_INTERVAL
+ dope
));
2136 adjust_stack (GEN_INT (PROBE_INTERVAL
+ dope
));
2139 /* Return an rtx representing the register or memory location
2140 in which a scalar value of data type VALTYPE
2141 was returned by a function call to function FUNC.
2142 FUNC is a FUNCTION_DECL, FNTYPE a FUNCTION_TYPE node if the precise
2143 function is known, otherwise 0.
2144 OUTGOING is 1 if on a machine with register windows this function
2145 should return the register in which the function will put its result
2149 hard_function_value (const_tree valtype
, const_tree func
, const_tree fntype
,
2150 int outgoing ATTRIBUTE_UNUSED
)
2154 val
= targetm
.calls
.function_value (valtype
, func
? func
: fntype
, outgoing
);
2157 && GET_MODE (val
) == BLKmode
)
2159 unsigned HOST_WIDE_INT bytes
= int_size_in_bytes (valtype
);
2160 opt_scalar_int_mode tmpmode
;
2162 /* int_size_in_bytes can return -1. We don't need a check here
2163 since the value of bytes will then be large enough that no
2164 mode will match anyway. */
2166 FOR_EACH_MODE_IN_CLASS (tmpmode
, MODE_INT
)
2168 /* Have we found a large enough mode? */
2169 if (GET_MODE_SIZE (tmpmode
.require ()) >= bytes
)
2173 PUT_MODE (val
, tmpmode
.require ());
2178 /* Return an rtx representing the register or memory location
2179 in which a scalar value of mode MODE was returned by a library call. */
2182 hard_libcall_value (machine_mode mode
, rtx fun
)
2184 return targetm
.calls
.libcall_value (mode
, fun
);
2187 /* Look up the tree code for a given rtx code
2188 to provide the arithmetic operation for real_arithmetic.
2189 The function returns an int because the caller may not know
2190 what `enum tree_code' means. */
2193 rtx_to_tree_code (enum rtx_code code
)
2195 enum tree_code tcode
;
2218 tcode
= LAST_AND_UNUSED_TREE_CODE
;
2221 return ((int) tcode
);
2224 #include "gt-explow.h"