2322 lines
70 KiB
C++
2322 lines
70 KiB
C++
/* Subroutines for manipulating rtx's in semantically interesting ways.
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Copyright (C) 1987-2022 Free Software Foundation, Inc.
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free
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Software Foundation; either version 3, or (at your option) any later
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version.
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GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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You should have received a copy of the GNU General Public License
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along with GCC; see the file COPYING3. If not see
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<http://www.gnu.org/licenses/>. */
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#include "config.h"
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#include "system.h"
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#include "coretypes.h"
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#include "target.h"
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#include "function.h"
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#include "rtl.h"
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#include "tree.h"
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#include "memmodel.h"
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#include "tm_p.h"
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#include "optabs.h"
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#include "expmed.h"
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#include "profile-count.h"
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#include "emit-rtl.h"
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#include "recog.h"
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#include "diagnostic-core.h"
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#include "stor-layout.h"
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#include "langhooks.h"
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#include "except.h"
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#include "dojump.h"
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#include "explow.h"
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#include "expr.h"
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#include "stringpool.h"
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#include "common/common-target.h"
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#include "output.h"
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static rtx break_out_memory_refs (rtx);
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/* Truncate and perhaps sign-extend C as appropriate for MODE. */
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HOST_WIDE_INT
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trunc_int_for_mode (HOST_WIDE_INT c, machine_mode mode)
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{
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/* Not scalar_int_mode because we also allow pointer bound modes. */
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scalar_mode smode = as_a <scalar_mode> (mode);
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int width = GET_MODE_PRECISION (smode);
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/* You want to truncate to a _what_? */
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gcc_assert (SCALAR_INT_MODE_P (mode));
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/* Canonicalize BImode to 0 and STORE_FLAG_VALUE. */
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if (smode == BImode)
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return c & 1 ? STORE_FLAG_VALUE : 0;
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/* Sign-extend for the requested mode. */
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if (width < HOST_BITS_PER_WIDE_INT)
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{
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HOST_WIDE_INT sign = 1;
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sign <<= width - 1;
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c &= (sign << 1) - 1;
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c ^= sign;
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c -= sign;
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}
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return c;
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}
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/* Likewise for polynomial values, using the sign-extended representation
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for each individual coefficient. */
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poly_int64
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trunc_int_for_mode (poly_int64 x, machine_mode mode)
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{
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for (unsigned int i = 0; i < NUM_POLY_INT_COEFFS; ++i)
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x.coeffs[i] = trunc_int_for_mode (x.coeffs[i], mode);
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return x;
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}
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/* Return an rtx for the sum of X and the integer C, given that X has
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mode MODE. INPLACE is true if X can be modified inplace or false
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if it must be treated as immutable. */
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rtx
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plus_constant (machine_mode mode, rtx x, poly_int64 c, bool inplace)
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{
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RTX_CODE code;
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rtx y;
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rtx tem;
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int all_constant = 0;
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gcc_assert (GET_MODE (x) == VOIDmode || GET_MODE (x) == mode);
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if (known_eq (c, 0))
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return x;
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restart:
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code = GET_CODE (x);
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y = x;
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switch (code)
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{
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CASE_CONST_SCALAR_INT:
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return immed_wide_int_const (wi::add (rtx_mode_t (x, mode), c), mode);
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case MEM:
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/* If this is a reference to the constant pool, try replacing it with
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a reference to a new constant. If the resulting address isn't
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valid, don't return it because we have no way to validize it. */
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if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
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&& CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
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{
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rtx cst = get_pool_constant (XEXP (x, 0));
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if (GET_CODE (cst) == CONST_VECTOR
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&& GET_MODE_INNER (GET_MODE (cst)) == mode)
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{
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cst = gen_lowpart (mode, cst);
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gcc_assert (cst);
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}
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else if (GET_MODE (cst) == VOIDmode
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&& get_pool_mode (XEXP (x, 0)) != mode)
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break;
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if (GET_MODE (cst) == VOIDmode || GET_MODE (cst) == mode)
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{
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tem = plus_constant (mode, cst, c);
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tem = force_const_mem (GET_MODE (x), tem);
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/* Targets may disallow some constants in the constant pool, thus
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force_const_mem may return NULL_RTX. */
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if (tem && memory_address_p (GET_MODE (tem), XEXP (tem, 0)))
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return tem;
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}
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}
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break;
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case CONST:
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/* If adding to something entirely constant, set a flag
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so that we can add a CONST around the result. */
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if (inplace && shared_const_p (x))
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inplace = false;
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x = XEXP (x, 0);
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all_constant = 1;
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goto restart;
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case SYMBOL_REF:
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case LABEL_REF:
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all_constant = 1;
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break;
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case PLUS:
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/* The interesting case is adding the integer to a sum. Look
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for constant term in the sum and combine with C. For an
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integer constant term or a constant term that is not an
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explicit integer, we combine or group them together anyway.
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We may not immediately return from the recursive call here, lest
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all_constant gets lost. */
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if (CONSTANT_P (XEXP (x, 1)))
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{
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rtx term = plus_constant (mode, XEXP (x, 1), c, inplace);
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if (term == const0_rtx)
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x = XEXP (x, 0);
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else if (inplace)
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XEXP (x, 1) = term;
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else
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x = gen_rtx_PLUS (mode, XEXP (x, 0), term);
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c = 0;
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}
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else if (rtx *const_loc = find_constant_term_loc (&y))
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{
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if (!inplace)
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{
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/* We need to be careful since X may be shared and we can't
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modify it in place. */
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x = copy_rtx (x);
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const_loc = find_constant_term_loc (&x);
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}
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*const_loc = plus_constant (mode, *const_loc, c, true);
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c = 0;
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}
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break;
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default:
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if (CONST_POLY_INT_P (x))
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return immed_wide_int_const (const_poly_int_value (x) + c, mode);
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break;
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}
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if (maybe_ne (c, 0))
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x = gen_rtx_PLUS (mode, x, gen_int_mode (c, mode));
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if (GET_CODE (x) == SYMBOL_REF || GET_CODE (x) == LABEL_REF)
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return x;
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else if (all_constant)
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return gen_rtx_CONST (mode, x);
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else
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return x;
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}
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/* If X is a sum, return a new sum like X but lacking any constant terms.
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Add all the removed constant terms into *CONSTPTR.
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X itself is not altered. The result != X if and only if
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it is not isomorphic to X. */
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rtx
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eliminate_constant_term (rtx x, rtx *constptr)
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{
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rtx x0, x1;
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rtx tem;
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if (GET_CODE (x) != PLUS)
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return x;
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/* First handle constants appearing at this level explicitly. */
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if (CONST_INT_P (XEXP (x, 1))
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&& (tem = simplify_binary_operation (PLUS, GET_MODE (x), *constptr,
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XEXP (x, 1))) != 0
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&& CONST_INT_P (tem))
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{
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*constptr = tem;
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return eliminate_constant_term (XEXP (x, 0), constptr);
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}
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tem = const0_rtx;
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x0 = eliminate_constant_term (XEXP (x, 0), &tem);
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x1 = eliminate_constant_term (XEXP (x, 1), &tem);
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if ((x1 != XEXP (x, 1) || x0 != XEXP (x, 0))
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&& (tem = simplify_binary_operation (PLUS, GET_MODE (x),
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*constptr, tem)) != 0
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&& CONST_INT_P (tem))
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{
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*constptr = tem;
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return gen_rtx_PLUS (GET_MODE (x), x0, x1);
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}
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return x;
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}
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/* Return a copy of X in which all memory references
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and all constants that involve symbol refs
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have been replaced with new temporary registers.
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Also emit code to load the memory locations and constants
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into those registers.
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If X contains no such constants or memory references,
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X itself (not a copy) is returned.
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If a constant is found in the address that is not a legitimate constant
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in an insn, it is left alone in the hope that it might be valid in the
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address.
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X may contain no arithmetic except addition, subtraction and multiplication.
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Values returned by expand_expr with 1 for sum_ok fit this constraint. */
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static rtx
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break_out_memory_refs (rtx x)
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{
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if (MEM_P (x)
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|| (CONSTANT_P (x) && CONSTANT_ADDRESS_P (x)
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&& GET_MODE (x) != VOIDmode))
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x = force_reg (GET_MODE (x), x);
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else if (GET_CODE (x) == PLUS || GET_CODE (x) == MINUS
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|| GET_CODE (x) == MULT)
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{
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rtx op0 = break_out_memory_refs (XEXP (x, 0));
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rtx op1 = break_out_memory_refs (XEXP (x, 1));
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if (op0 != XEXP (x, 0) || op1 != XEXP (x, 1))
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x = simplify_gen_binary (GET_CODE (x), GET_MODE (x), op0, op1);
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}
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return x;
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}
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/* Given X, a memory address in address space AS' pointer mode, convert it to
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an address in the address space's address mode, or vice versa (TO_MODE says
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which way). We take advantage of the fact that pointers are not allowed to
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overflow by commuting arithmetic operations over conversions so that address
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arithmetic insns can be used. IN_CONST is true if this conversion is inside
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a CONST. NO_EMIT is true if no insns should be emitted, and instead
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it should return NULL if it can't be simplified without emitting insns. */
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rtx
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convert_memory_address_addr_space_1 (scalar_int_mode to_mode ATTRIBUTE_UNUSED,
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rtx x, addr_space_t as ATTRIBUTE_UNUSED,
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bool in_const ATTRIBUTE_UNUSED,
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bool no_emit ATTRIBUTE_UNUSED)
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{
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#ifndef POINTERS_EXTEND_UNSIGNED
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gcc_assert (GET_MODE (x) == to_mode || GET_MODE (x) == VOIDmode);
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return x;
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#else /* defined(POINTERS_EXTEND_UNSIGNED) */
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scalar_int_mode pointer_mode, address_mode, from_mode;
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rtx temp;
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enum rtx_code code;
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/* If X already has the right mode, just return it. */
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if (GET_MODE (x) == to_mode)
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return x;
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||
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pointer_mode = targetm.addr_space.pointer_mode (as);
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address_mode = targetm.addr_space.address_mode (as);
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from_mode = to_mode == pointer_mode ? address_mode : pointer_mode;
|
||
|
||
/* Here we handle some special cases. If none of them apply, fall through
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to the default case. */
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switch (GET_CODE (x))
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{
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CASE_CONST_SCALAR_INT:
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if (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (from_mode))
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code = TRUNCATE;
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else if (POINTERS_EXTEND_UNSIGNED < 0)
|
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break;
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else if (POINTERS_EXTEND_UNSIGNED > 0)
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code = ZERO_EXTEND;
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else
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code = SIGN_EXTEND;
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temp = simplify_unary_operation (code, to_mode, x, from_mode);
|
||
if (temp)
|
||
return temp;
|
||
break;
|
||
|
||
case SUBREG:
|
||
if ((SUBREG_PROMOTED_VAR_P (x) || REG_POINTER (SUBREG_REG (x)))
|
||
&& GET_MODE (SUBREG_REG (x)) == to_mode)
|
||
return SUBREG_REG (x);
|
||
break;
|
||
|
||
case LABEL_REF:
|
||
temp = gen_rtx_LABEL_REF (to_mode, label_ref_label (x));
|
||
LABEL_REF_NONLOCAL_P (temp) = LABEL_REF_NONLOCAL_P (x);
|
||
return temp;
|
||
|
||
case SYMBOL_REF:
|
||
temp = shallow_copy_rtx (x);
|
||
PUT_MODE (temp, to_mode);
|
||
return temp;
|
||
|
||
case CONST:
|
||
temp = convert_memory_address_addr_space_1 (to_mode, XEXP (x, 0), as,
|
||
true, no_emit);
|
||
return temp ? gen_rtx_CONST (to_mode, temp) : temp;
|
||
|
||
case PLUS:
|
||
case MULT:
|
||
/* For addition we can safely permute the conversion and addition
|
||
operation if one operand is a constant and converting the constant
|
||
does not change it or if one operand is a constant and we are
|
||
using a ptr_extend instruction (POINTERS_EXTEND_UNSIGNED < 0).
|
||
We can always safely permute them if we are making the address
|
||
narrower. Inside a CONST RTL, this is safe for both pointers
|
||
zero or sign extended as pointers cannot wrap. */
|
||
if (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (from_mode)
|
||
|| (GET_CODE (x) == PLUS
|
||
&& CONST_INT_P (XEXP (x, 1))
|
||
&& ((in_const && POINTERS_EXTEND_UNSIGNED != 0)
|
||
|| XEXP (x, 1) == convert_memory_address_addr_space_1
|
||
(to_mode, XEXP (x, 1), as, in_const,
|
||
no_emit)
|
||
|| POINTERS_EXTEND_UNSIGNED < 0)))
|
||
{
|
||
temp = convert_memory_address_addr_space_1 (to_mode, XEXP (x, 0),
|
||
as, in_const, no_emit);
|
||
return (temp ? gen_rtx_fmt_ee (GET_CODE (x), to_mode,
|
||
temp, XEXP (x, 1))
|
||
: temp);
|
||
}
|
||
break;
|
||
|
||
case UNSPEC:
|
||
/* Assume that all UNSPECs in a constant address can be converted
|
||
operand-by-operand. We could add a target hook if some targets
|
||
require different behavior. */
|
||
if (in_const && GET_MODE (x) == from_mode)
|
||
{
|
||
unsigned int n = XVECLEN (x, 0);
|
||
rtvec v = gen_rtvec (n);
|
||
for (unsigned int i = 0; i < n; ++i)
|
||
{
|
||
rtx op = XVECEXP (x, 0, i);
|
||
if (GET_MODE (op) == from_mode)
|
||
op = convert_memory_address_addr_space_1 (to_mode, op, as,
|
||
in_const, no_emit);
|
||
RTVEC_ELT (v, i) = op;
|
||
}
|
||
return gen_rtx_UNSPEC (to_mode, v, XINT (x, 1));
|
||
}
|
||
break;
|
||
|
||
default:
|
||
break;
|
||
}
|
||
|
||
if (no_emit)
|
||
return NULL_RTX;
|
||
|
||
return convert_modes (to_mode, from_mode,
|
||
x, POINTERS_EXTEND_UNSIGNED);
|
||
#endif /* defined(POINTERS_EXTEND_UNSIGNED) */
|
||
}
|
||
|
||
/* Given X, a memory address in address space AS' pointer mode, convert it to
|
||
an address in the address space's address mode, or vice versa (TO_MODE says
|
||
which way). We take advantage of the fact that pointers are not allowed to
|
||
overflow by commuting arithmetic operations over conversions so that address
|
||
arithmetic insns can be used. */
|
||
|
||
rtx
|
||
convert_memory_address_addr_space (scalar_int_mode to_mode, rtx x,
|
||
addr_space_t as)
|
||
{
|
||
return convert_memory_address_addr_space_1 (to_mode, x, as, false, false);
|
||
}
|
||
|
||
|
||
/* Return something equivalent to X but valid as a memory address for something
|
||
of mode MODE in the named address space AS. When X is not itself valid,
|
||
this works by copying X or subexpressions of it into registers. */
|
||
|
||
rtx
|
||
memory_address_addr_space (machine_mode mode, rtx x, addr_space_t as)
|
||
{
|
||
rtx oldx = x;
|
||
scalar_int_mode address_mode = targetm.addr_space.address_mode (as);
|
||
|
||
x = convert_memory_address_addr_space (address_mode, x, as);
|
||
|
||
/* By passing constant addresses through registers
|
||
we get a chance to cse them. */
|
||
if (! cse_not_expected && CONSTANT_P (x) && CONSTANT_ADDRESS_P (x))
|
||
x = force_reg (address_mode, x);
|
||
|
||
/* We get better cse by rejecting indirect addressing at this stage.
|
||
Let the combiner create indirect addresses where appropriate.
|
||
For now, generate the code so that the subexpressions useful to share
|
||
are visible. But not if cse won't be done! */
|
||
else
|
||
{
|
||
if (! cse_not_expected && !REG_P (x))
|
||
x = break_out_memory_refs (x);
|
||
|
||
/* At this point, any valid address is accepted. */
|
||
if (memory_address_addr_space_p (mode, x, as))
|
||
goto done;
|
||
|
||
/* If it was valid before but breaking out memory refs invalidated it,
|
||
use it the old way. */
|
||
if (memory_address_addr_space_p (mode, oldx, as))
|
||
{
|
||
x = oldx;
|
||
goto done;
|
||
}
|
||
|
||
/* Perform machine-dependent transformations on X
|
||
in certain cases. This is not necessary since the code
|
||
below can handle all possible cases, but machine-dependent
|
||
transformations can make better code. */
|
||
{
|
||
rtx orig_x = x;
|
||
x = targetm.addr_space.legitimize_address (x, oldx, mode, as);
|
||
if (orig_x != x && memory_address_addr_space_p (mode, x, as))
|
||
goto done;
|
||
}
|
||
|
||
/* PLUS and MULT can appear in special ways
|
||
as the result of attempts to make an address usable for indexing.
|
||
Usually they are dealt with by calling force_operand, below.
|
||
But a sum containing constant terms is special
|
||
if removing them makes the sum a valid address:
|
||
then we generate that address in a register
|
||
and index off of it. We do this because it often makes
|
||
shorter code, and because the addresses thus generated
|
||
in registers often become common subexpressions. */
|
||
if (GET_CODE (x) == PLUS)
|
||
{
|
||
rtx constant_term = const0_rtx;
|
||
rtx y = eliminate_constant_term (x, &constant_term);
|
||
if (constant_term == const0_rtx
|
||
|| ! memory_address_addr_space_p (mode, y, as))
|
||
x = force_operand (x, NULL_RTX);
|
||
else
|
||
{
|
||
y = gen_rtx_PLUS (GET_MODE (x), copy_to_reg (y), constant_term);
|
||
if (! memory_address_addr_space_p (mode, y, as))
|
||
x = force_operand (x, NULL_RTX);
|
||
else
|
||
x = y;
|
||
}
|
||
}
|
||
|
||
else if (GET_CODE (x) == MULT || GET_CODE (x) == MINUS)
|
||
x = force_operand (x, NULL_RTX);
|
||
|
||
/* If we have a register that's an invalid address,
|
||
it must be a hard reg of the wrong class. Copy it to a pseudo. */
|
||
else if (REG_P (x))
|
||
x = copy_to_reg (x);
|
||
|
||
/* Last resort: copy the value to a register, since
|
||
the register is a valid address. */
|
||
else
|
||
x = force_reg (address_mode, x);
|
||
}
|
||
|
||
done:
|
||
|
||
gcc_assert (memory_address_addr_space_p (mode, x, as));
|
||
/* If we didn't change the address, we are done. Otherwise, mark
|
||
a reg as a pointer if we have REG or REG + CONST_INT. */
|
||
if (oldx == x)
|
||
return x;
|
||
else if (REG_P (x))
|
||
mark_reg_pointer (x, BITS_PER_UNIT);
|
||
else if (GET_CODE (x) == PLUS
|
||
&& REG_P (XEXP (x, 0))
|
||
&& CONST_INT_P (XEXP (x, 1)))
|
||
mark_reg_pointer (XEXP (x, 0), BITS_PER_UNIT);
|
||
|
||
/* OLDX may have been the address on a temporary. Update the address
|
||
to indicate that X is now used. */
|
||
update_temp_slot_address (oldx, x);
|
||
|
||
return x;
|
||
}
|
||
|
||
/* Convert a mem ref into one with a valid memory address.
|
||
Pass through anything else unchanged. */
|
||
|
||
rtx
|
||
validize_mem (rtx ref)
|
||
{
|
||
if (!MEM_P (ref))
|
||
return ref;
|
||
ref = use_anchored_address (ref);
|
||
if (memory_address_addr_space_p (GET_MODE (ref), XEXP (ref, 0),
|
||
MEM_ADDR_SPACE (ref)))
|
||
return ref;
|
||
|
||
/* Don't alter REF itself, since that is probably a stack slot. */
|
||
return replace_equiv_address (ref, XEXP (ref, 0));
|
||
}
|
||
|
||
/* If X is a memory reference to a member of an object block, try rewriting
|
||
it to use an anchor instead. Return the new memory reference on success
|
||
and the old one on failure. */
|
||
|
||
rtx
|
||
use_anchored_address (rtx x)
|
||
{
|
||
rtx base;
|
||
HOST_WIDE_INT offset;
|
||
machine_mode mode;
|
||
|
||
if (!flag_section_anchors)
|
||
return x;
|
||
|
||
if (!MEM_P (x))
|
||
return x;
|
||
|
||
/* Split the address into a base and offset. */
|
||
base = XEXP (x, 0);
|
||
offset = 0;
|
||
if (GET_CODE (base) == CONST
|
||
&& GET_CODE (XEXP (base, 0)) == PLUS
|
||
&& CONST_INT_P (XEXP (XEXP (base, 0), 1)))
|
||
{
|
||
offset += INTVAL (XEXP (XEXP (base, 0), 1));
|
||
base = XEXP (XEXP (base, 0), 0);
|
||
}
|
||
|
||
/* Check whether BASE is suitable for anchors. */
|
||
if (GET_CODE (base) != SYMBOL_REF
|
||
|| !SYMBOL_REF_HAS_BLOCK_INFO_P (base)
|
||
|| SYMBOL_REF_ANCHOR_P (base)
|
||
|| SYMBOL_REF_BLOCK (base) == NULL
|
||
|| !targetm.use_anchors_for_symbol_p (base))
|
||
return x;
|
||
|
||
/* Decide where BASE is going to be. */
|
||
place_block_symbol (base);
|
||
|
||
/* Get the anchor we need to use. */
|
||
offset += SYMBOL_REF_BLOCK_OFFSET (base);
|
||
base = get_section_anchor (SYMBOL_REF_BLOCK (base), offset,
|
||
SYMBOL_REF_TLS_MODEL (base));
|
||
|
||
/* Work out the offset from the anchor. */
|
||
offset -= SYMBOL_REF_BLOCK_OFFSET (base);
|
||
|
||
/* If we're going to run a CSE pass, force the anchor into a register.
|
||
We will then be able to reuse registers for several accesses, if the
|
||
target costs say that that's worthwhile. */
|
||
mode = GET_MODE (base);
|
||
if (!cse_not_expected)
|
||
base = force_reg (mode, base);
|
||
|
||
return replace_equiv_address (x, plus_constant (mode, base, offset));
|
||
}
|
||
|
||
/* Copy the value or contents of X to a new temp reg and return that reg. */
|
||
|
||
rtx
|
||
copy_to_reg (rtx x)
|
||
{
|
||
rtx temp = gen_reg_rtx (GET_MODE (x));
|
||
|
||
/* If not an operand, must be an address with PLUS and MULT so
|
||
do the computation. */
|
||
if (! general_operand (x, VOIDmode))
|
||
x = force_operand (x, temp);
|
||
|
||
if (x != temp)
|
||
emit_move_insn (temp, x);
|
||
|
||
return temp;
|
||
}
|
||
|
||
/* Like copy_to_reg but always give the new register mode Pmode
|
||
in case X is a constant. */
|
||
|
||
rtx
|
||
copy_addr_to_reg (rtx x)
|
||
{
|
||
return copy_to_mode_reg (Pmode, x);
|
||
}
|
||
|
||
/* Like copy_to_reg but always give the new register mode MODE
|
||
in case X is a constant. */
|
||
|
||
rtx
|
||
copy_to_mode_reg (machine_mode mode, rtx x)
|
||
{
|
||
rtx temp = gen_reg_rtx (mode);
|
||
|
||
/* If not an operand, must be an address with PLUS and MULT so
|
||
do the computation. */
|
||
if (! general_operand (x, VOIDmode))
|
||
x = force_operand (x, temp);
|
||
|
||
gcc_assert (GET_MODE (x) == mode || GET_MODE (x) == VOIDmode);
|
||
if (x != temp)
|
||
emit_move_insn (temp, x);
|
||
return temp;
|
||
}
|
||
|
||
/* Load X into a register if it is not already one.
|
||
Use mode MODE for the register.
|
||
X should be valid for mode MODE, but it may be a constant which
|
||
is valid for all integer modes; that's why caller must specify MODE.
|
||
|
||
The caller must not alter the value in the register we return,
|
||
since we mark it as a "constant" register. */
|
||
|
||
rtx
|
||
force_reg (machine_mode mode, rtx x)
|
||
{
|
||
rtx temp, set;
|
||
rtx_insn *insn;
|
||
|
||
if (REG_P (x))
|
||
return x;
|
||
|
||
if (general_operand (x, mode))
|
||
{
|
||
temp = gen_reg_rtx (mode);
|
||
insn = emit_move_insn (temp, x);
|
||
}
|
||
else
|
||
{
|
||
temp = force_operand (x, NULL_RTX);
|
||
if (REG_P (temp))
|
||
insn = get_last_insn ();
|
||
else
|
||
{
|
||
rtx temp2 = gen_reg_rtx (mode);
|
||
insn = emit_move_insn (temp2, temp);
|
||
temp = temp2;
|
||
}
|
||
}
|
||
|
||
/* Let optimizers know that TEMP's value never changes
|
||
and that X can be substituted for it. Don't get confused
|
||
if INSN set something else (such as a SUBREG of TEMP). */
|
||
if (CONSTANT_P (x)
|
||
&& (set = single_set (insn)) != 0
|
||
&& SET_DEST (set) == temp
|
||
&& ! rtx_equal_p (x, SET_SRC (set)))
|
||
set_unique_reg_note (insn, REG_EQUAL, x);
|
||
|
||
/* Let optimizers know that TEMP is a pointer, and if so, the
|
||
known alignment of that pointer. */
|
||
{
|
||
unsigned align = 0;
|
||
if (GET_CODE (x) == SYMBOL_REF)
|
||
{
|
||
align = BITS_PER_UNIT;
|
||
if (SYMBOL_REF_DECL (x) && DECL_P (SYMBOL_REF_DECL (x)))
|
||
align = DECL_ALIGN (SYMBOL_REF_DECL (x));
|
||
}
|
||
else if (GET_CODE (x) == LABEL_REF)
|
||
align = BITS_PER_UNIT;
|
||
else if (GET_CODE (x) == CONST
|
||
&& GET_CODE (XEXP (x, 0)) == PLUS
|
||
&& GET_CODE (XEXP (XEXP (x, 0), 0)) == SYMBOL_REF
|
||
&& CONST_INT_P (XEXP (XEXP (x, 0), 1)))
|
||
{
|
||
rtx s = XEXP (XEXP (x, 0), 0);
|
||
rtx c = XEXP (XEXP (x, 0), 1);
|
||
unsigned sa, ca;
|
||
|
||
sa = BITS_PER_UNIT;
|
||
if (SYMBOL_REF_DECL (s) && DECL_P (SYMBOL_REF_DECL (s)))
|
||
sa = DECL_ALIGN (SYMBOL_REF_DECL (s));
|
||
|
||
if (INTVAL (c) == 0)
|
||
align = sa;
|
||
else
|
||
{
|
||
ca = ctz_hwi (INTVAL (c)) * BITS_PER_UNIT;
|
||
align = MIN (sa, ca);
|
||
}
|
||
}
|
||
|
||
if (align || (MEM_P (x) && MEM_POINTER (x)))
|
||
mark_reg_pointer (temp, align);
|
||
}
|
||
|
||
return temp;
|
||
}
|
||
|
||
/* If X is a memory ref, copy its contents to a new temp reg and return
|
||
that reg. Otherwise, return X. */
|
||
|
||
rtx
|
||
force_not_mem (rtx x)
|
||
{
|
||
rtx temp;
|
||
|
||
if (!MEM_P (x) || GET_MODE (x) == BLKmode)
|
||
return x;
|
||
|
||
temp = gen_reg_rtx (GET_MODE (x));
|
||
|
||
if (MEM_POINTER (x))
|
||
REG_POINTER (temp) = 1;
|
||
|
||
emit_move_insn (temp, x);
|
||
return temp;
|
||
}
|
||
|
||
/* Copy X to TARGET (if it's nonzero and a reg)
|
||
or to a new temp reg and return that reg.
|
||
MODE is the mode to use for X in case it is a constant. */
|
||
|
||
rtx
|
||
copy_to_suggested_reg (rtx x, rtx target, machine_mode mode)
|
||
{
|
||
rtx temp;
|
||
|
||
if (target && REG_P (target))
|
||
temp = target;
|
||
else
|
||
temp = gen_reg_rtx (mode);
|
||
|
||
emit_move_insn (temp, x);
|
||
return temp;
|
||
}
|
||
|
||
/* Return the mode to use to pass or return a scalar of TYPE and MODE.
|
||
PUNSIGNEDP points to the signedness of the type and may be adjusted
|
||
to show what signedness to use on extension operations.
|
||
|
||
FOR_RETURN is nonzero if the caller is promoting the return value
|
||
of FNDECL, else it is for promoting args. */
|
||
|
||
machine_mode
|
||
promote_function_mode (const_tree type, machine_mode mode, int *punsignedp,
|
||
const_tree funtype, int for_return)
|
||
{
|
||
/* Called without a type node for a libcall. */
|
||
if (type == NULL_TREE)
|
||
{
|
||
if (INTEGRAL_MODE_P (mode))
|
||
return targetm.calls.promote_function_mode (NULL_TREE, mode,
|
||
punsignedp, funtype,
|
||
for_return);
|
||
else
|
||
return mode;
|
||
}
|
||
|
||
switch (TREE_CODE (type))
|
||
{
|
||
case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE:
|
||
case REAL_TYPE: case OFFSET_TYPE: case FIXED_POINT_TYPE:
|
||
case POINTER_TYPE: case REFERENCE_TYPE:
|
||
return targetm.calls.promote_function_mode (type, mode, punsignedp, funtype,
|
||
for_return);
|
||
|
||
default:
|
||
return mode;
|
||
}
|
||
}
|
||
/* Return the mode to use to store a scalar of TYPE and MODE.
|
||
PUNSIGNEDP points to the signedness of the type and may be adjusted
|
||
to show what signedness to use on extension operations. */
|
||
|
||
machine_mode
|
||
promote_mode (const_tree type ATTRIBUTE_UNUSED, machine_mode mode,
|
||
int *punsignedp ATTRIBUTE_UNUSED)
|
||
{
|
||
#ifdef PROMOTE_MODE
|
||
enum tree_code code;
|
||
int unsignedp;
|
||
scalar_mode smode;
|
||
#endif
|
||
|
||
/* For libcalls this is invoked without TYPE from the backends
|
||
TARGET_PROMOTE_FUNCTION_MODE hooks. Don't do anything in that
|
||
case. */
|
||
if (type == NULL_TREE)
|
||
return mode;
|
||
|
||
/* FIXME: this is the same logic that was there until GCC 4.4, but we
|
||
probably want to test POINTERS_EXTEND_UNSIGNED even if PROMOTE_MODE
|
||
is not defined. The affected targets are M32C, S390, SPARC. */
|
||
#ifdef PROMOTE_MODE
|
||
code = TREE_CODE (type);
|
||
unsignedp = *punsignedp;
|
||
|
||
switch (code)
|
||
{
|
||
case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE:
|
||
case REAL_TYPE: case OFFSET_TYPE: case FIXED_POINT_TYPE:
|
||
/* Values of these types always have scalar mode. */
|
||
smode = as_a <scalar_mode> (mode);
|
||
PROMOTE_MODE (smode, unsignedp, type);
|
||
*punsignedp = unsignedp;
|
||
return smode;
|
||
|
||
#ifdef POINTERS_EXTEND_UNSIGNED
|
||
case REFERENCE_TYPE:
|
||
case POINTER_TYPE:
|
||
*punsignedp = POINTERS_EXTEND_UNSIGNED;
|
||
return targetm.addr_space.address_mode
|
||
(TYPE_ADDR_SPACE (TREE_TYPE (type)));
|
||
#endif
|
||
|
||
default:
|
||
return mode;
|
||
}
|
||
#else
|
||
return mode;
|
||
#endif
|
||
}
|
||
|
||
|
||
/* Use one of promote_mode or promote_function_mode to find the promoted
|
||
mode of DECL. If PUNSIGNEDP is not NULL, store there the unsignedness
|
||
of DECL after promotion. */
|
||
|
||
machine_mode
|
||
promote_decl_mode (const_tree decl, int *punsignedp)
|
||
{
|
||
tree type = TREE_TYPE (decl);
|
||
int unsignedp = TYPE_UNSIGNED (type);
|
||
machine_mode mode = DECL_MODE (decl);
|
||
machine_mode pmode;
|
||
|
||
if (TREE_CODE (decl) == RESULT_DECL && !DECL_BY_REFERENCE (decl))
|
||
pmode = promote_function_mode (type, mode, &unsignedp,
|
||
TREE_TYPE (current_function_decl), 1);
|
||
else if (TREE_CODE (decl) == RESULT_DECL || TREE_CODE (decl) == PARM_DECL)
|
||
pmode = promote_function_mode (type, mode, &unsignedp,
|
||
TREE_TYPE (current_function_decl), 2);
|
||
else
|
||
pmode = promote_mode (type, mode, &unsignedp);
|
||
|
||
if (punsignedp)
|
||
*punsignedp = unsignedp;
|
||
return pmode;
|
||
}
|
||
|
||
/* Return the promoted mode for name. If it is a named SSA_NAME, it
|
||
is the same as promote_decl_mode. Otherwise, it is the promoted
|
||
mode of a temp decl of same type as the SSA_NAME, if we had created
|
||
one. */
|
||
|
||
machine_mode
|
||
promote_ssa_mode (const_tree name, int *punsignedp)
|
||
{
|
||
gcc_assert (TREE_CODE (name) == SSA_NAME);
|
||
|
||
/* Partitions holding parms and results must be promoted as expected
|
||
by function.cc. */
|
||
if (SSA_NAME_VAR (name)
|
||
&& (TREE_CODE (SSA_NAME_VAR (name)) == PARM_DECL
|
||
|| TREE_CODE (SSA_NAME_VAR (name)) == RESULT_DECL))
|
||
{
|
||
machine_mode mode = promote_decl_mode (SSA_NAME_VAR (name), punsignedp);
|
||
if (mode != BLKmode)
|
||
return mode;
|
||
}
|
||
|
||
tree type = TREE_TYPE (name);
|
||
int unsignedp = TYPE_UNSIGNED (type);
|
||
machine_mode pmode = promote_mode (type, TYPE_MODE (type), &unsignedp);
|
||
if (punsignedp)
|
||
*punsignedp = unsignedp;
|
||
|
||
return pmode;
|
||
}
|
||
|
||
|
||
|
||
/* Controls the behavior of {anti_,}adjust_stack. */
|
||
static bool suppress_reg_args_size;
|
||
|
||
/* A helper for adjust_stack and anti_adjust_stack. */
|
||
|
||
static void
|
||
adjust_stack_1 (rtx adjust, bool anti_p)
|
||
{
|
||
rtx temp;
|
||
rtx_insn *insn;
|
||
|
||
/* Hereafter anti_p means subtract_p. */
|
||
if (!STACK_GROWS_DOWNWARD)
|
||
anti_p = !anti_p;
|
||
|
||
temp = expand_binop (Pmode,
|
||
anti_p ? sub_optab : add_optab,
|
||
stack_pointer_rtx, adjust, stack_pointer_rtx, 0,
|
||
OPTAB_LIB_WIDEN);
|
||
|
||
if (temp != stack_pointer_rtx)
|
||
insn = emit_move_insn (stack_pointer_rtx, temp);
|
||
else
|
||
{
|
||
insn = get_last_insn ();
|
||
temp = single_set (insn);
|
||
gcc_assert (temp != NULL && SET_DEST (temp) == stack_pointer_rtx);
|
||
}
|
||
|
||
if (!suppress_reg_args_size)
|
||
add_args_size_note (insn, stack_pointer_delta);
|
||
}
|
||
|
||
/* Adjust the stack pointer by ADJUST (an rtx for a number of bytes).
|
||
This pops when ADJUST is positive. ADJUST need not be constant. */
|
||
|
||
void
|
||
adjust_stack (rtx adjust)
|
||
{
|
||
if (adjust == const0_rtx)
|
||
return;
|
||
|
||
/* We expect all variable sized adjustments to be multiple of
|
||
PREFERRED_STACK_BOUNDARY. */
|
||
poly_int64 const_adjust;
|
||
if (poly_int_rtx_p (adjust, &const_adjust))
|
||
stack_pointer_delta -= const_adjust;
|
||
|
||
adjust_stack_1 (adjust, false);
|
||
}
|
||
|
||
/* Adjust the stack pointer by minus ADJUST (an rtx for a number of bytes).
|
||
This pushes when ADJUST is positive. ADJUST need not be constant. */
|
||
|
||
void
|
||
anti_adjust_stack (rtx adjust)
|
||
{
|
||
if (adjust == const0_rtx)
|
||
return;
|
||
|
||
/* We expect all variable sized adjustments to be multiple of
|
||
PREFERRED_STACK_BOUNDARY. */
|
||
poly_int64 const_adjust;
|
||
if (poly_int_rtx_p (adjust, &const_adjust))
|
||
stack_pointer_delta += const_adjust;
|
||
|
||
adjust_stack_1 (adjust, true);
|
||
}
|
||
|
||
/* Round the size of a block to be pushed up to the boundary required
|
||
by this machine. SIZE is the desired size, which need not be constant. */
|
||
|
||
static rtx
|
||
round_push (rtx size)
|
||
{
|
||
rtx align_rtx, alignm1_rtx;
|
||
|
||
if (!SUPPORTS_STACK_ALIGNMENT
|
||
|| crtl->preferred_stack_boundary == MAX_SUPPORTED_STACK_ALIGNMENT)
|
||
{
|
||
int align = crtl->preferred_stack_boundary / BITS_PER_UNIT;
|
||
|
||
if (align == 1)
|
||
return size;
|
||
|
||
if (CONST_INT_P (size))
|
||
{
|
||
HOST_WIDE_INT new_size = (INTVAL (size) + align - 1) / align * align;
|
||
|
||
if (INTVAL (size) != new_size)
|
||
size = GEN_INT (new_size);
|
||
return size;
|
||
}
|
||
|
||
align_rtx = GEN_INT (align);
|
||
alignm1_rtx = GEN_INT (align - 1);
|
||
}
|
||
else
|
||
{
|
||
/* If crtl->preferred_stack_boundary might still grow, use
|
||
virtual_preferred_stack_boundary_rtx instead. This will be
|
||
substituted by the right value in vregs pass and optimized
|
||
during combine. */
|
||
align_rtx = virtual_preferred_stack_boundary_rtx;
|
||
alignm1_rtx = force_operand (plus_constant (Pmode, align_rtx, -1),
|
||
NULL_RTX);
|
||
}
|
||
|
||
/* CEIL_DIV_EXPR needs to worry about the addition overflowing,
|
||
but we know it can't. So add ourselves and then do
|
||
TRUNC_DIV_EXPR. */
|
||
size = expand_binop (Pmode, add_optab, size, alignm1_rtx,
|
||
NULL_RTX, 1, OPTAB_LIB_WIDEN);
|
||
size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size, align_rtx,
|
||
NULL_RTX, 1);
|
||
size = expand_mult (Pmode, size, align_rtx, NULL_RTX, 1);
|
||
|
||
return size;
|
||
}
|
||
|
||
/* Save the stack pointer for the purpose in SAVE_LEVEL. PSAVE is a pointer
|
||
to a previously-created save area. If no save area has been allocated,
|
||
this function will allocate one. If a save area is specified, it
|
||
must be of the proper mode. */
|
||
|
||
void
|
||
emit_stack_save (enum save_level save_level, rtx *psave)
|
||
{
|
||
rtx sa = *psave;
|
||
/* The default is that we use a move insn and save in a Pmode object. */
|
||
rtx_insn *(*fcn) (rtx, rtx) = gen_move_insn;
|
||
machine_mode mode = STACK_SAVEAREA_MODE (save_level);
|
||
|
||
/* See if this machine has anything special to do for this kind of save. */
|
||
switch (save_level)
|
||
{
|
||
case SAVE_BLOCK:
|
||
if (targetm.have_save_stack_block ())
|
||
fcn = targetm.gen_save_stack_block;
|
||
break;
|
||
case SAVE_FUNCTION:
|
||
if (targetm.have_save_stack_function ())
|
||
fcn = targetm.gen_save_stack_function;
|
||
break;
|
||
case SAVE_NONLOCAL:
|
||
if (targetm.have_save_stack_nonlocal ())
|
||
fcn = targetm.gen_save_stack_nonlocal;
|
||
break;
|
||
default:
|
||
break;
|
||
}
|
||
|
||
/* If there is no save area and we have to allocate one, do so. Otherwise
|
||
verify the save area is the proper mode. */
|
||
|
||
if (sa == 0)
|
||
{
|
||
if (mode != VOIDmode)
|
||
{
|
||
if (save_level == SAVE_NONLOCAL)
|
||
*psave = sa = assign_stack_local (mode, GET_MODE_SIZE (mode), 0);
|
||
else
|
||
*psave = sa = gen_reg_rtx (mode);
|
||
}
|
||
}
|
||
|
||
do_pending_stack_adjust ();
|
||
if (sa != 0)
|
||
sa = validize_mem (sa);
|
||
emit_insn (fcn (sa, stack_pointer_rtx));
|
||
}
|
||
|
||
/* Restore the stack pointer for the purpose in SAVE_LEVEL. SA is the save
|
||
area made by emit_stack_save. If it is zero, we have nothing to do. */
|
||
|
||
void
|
||
emit_stack_restore (enum save_level save_level, rtx sa)
|
||
{
|
||
/* The default is that we use a move insn. */
|
||
rtx_insn *(*fcn) (rtx, rtx) = gen_move_insn;
|
||
|
||
/* If stack_realign_drap, the x86 backend emits a prologue that aligns both
|
||
STACK_POINTER and HARD_FRAME_POINTER.
|
||
If stack_realign_fp, the x86 backend emits a prologue that aligns only
|
||
STACK_POINTER. This renders the HARD_FRAME_POINTER unusable for accessing
|
||
aligned variables, which is reflected in ix86_can_eliminate.
|
||
We normally still have the realigned STACK_POINTER that we can use.
|
||
But if there is a stack restore still present at reload, it can trigger
|
||
mark_not_eliminable for the STACK_POINTER, leaving no way to eliminate
|
||
FRAME_POINTER into a hard reg.
|
||
To prevent this situation, we force need_drap if we emit a stack
|
||
restore. */
|
||
if (SUPPORTS_STACK_ALIGNMENT)
|
||
crtl->need_drap = true;
|
||
|
||
/* See if this machine has anything special to do for this kind of save. */
|
||
switch (save_level)
|
||
{
|
||
case SAVE_BLOCK:
|
||
if (targetm.have_restore_stack_block ())
|
||
fcn = targetm.gen_restore_stack_block;
|
||
break;
|
||
case SAVE_FUNCTION:
|
||
if (targetm.have_restore_stack_function ())
|
||
fcn = targetm.gen_restore_stack_function;
|
||
break;
|
||
case SAVE_NONLOCAL:
|
||
if (targetm.have_restore_stack_nonlocal ())
|
||
fcn = targetm.gen_restore_stack_nonlocal;
|
||
break;
|
||
default:
|
||
break;
|
||
}
|
||
|
||
if (sa != 0)
|
||
{
|
||
sa = validize_mem (sa);
|
||
/* These clobbers prevent the scheduler from moving
|
||
references to variable arrays below the code
|
||
that deletes (pops) the arrays. */
|
||
emit_clobber (gen_rtx_MEM (BLKmode, gen_rtx_SCRATCH (VOIDmode)));
|
||
emit_clobber (gen_rtx_MEM (BLKmode, stack_pointer_rtx));
|
||
}
|
||
|
||
discard_pending_stack_adjust ();
|
||
|
||
emit_insn (fcn (stack_pointer_rtx, sa));
|
||
}
|
||
|
||
/* Invoke emit_stack_save on the nonlocal_goto_save_area for the current
|
||
function. This should be called whenever we allocate or deallocate
|
||
dynamic stack space. */
|
||
|
||
void
|
||
update_nonlocal_goto_save_area (void)
|
||
{
|
||
tree t_save;
|
||
rtx r_save;
|
||
|
||
/* The nonlocal_goto_save_area object is an array of N pointers. The
|
||
first one is used for the frame pointer save; the rest are sized by
|
||
STACK_SAVEAREA_MODE. Create a reference to array index 1, the first
|
||
of the stack save area slots. */
|
||
t_save = build4 (ARRAY_REF,
|
||
TREE_TYPE (TREE_TYPE (cfun->nonlocal_goto_save_area)),
|
||
cfun->nonlocal_goto_save_area,
|
||
integer_one_node, NULL_TREE, NULL_TREE);
|
||
r_save = expand_expr (t_save, NULL_RTX, VOIDmode, EXPAND_WRITE);
|
||
|
||
emit_stack_save (SAVE_NONLOCAL, &r_save);
|
||
}
|
||
|
||
/* Record a new stack level for the current function. This should be called
|
||
whenever we allocate or deallocate dynamic stack space. */
|
||
|
||
void
|
||
record_new_stack_level (void)
|
||
{
|
||
/* Record the new stack level for nonlocal gotos. */
|
||
if (cfun->nonlocal_goto_save_area)
|
||
update_nonlocal_goto_save_area ();
|
||
|
||
/* Record the new stack level for SJLJ exceptions. */
|
||
if (targetm_common.except_unwind_info (&global_options) == UI_SJLJ)
|
||
update_sjlj_context ();
|
||
}
|
||
|
||
/* Return an rtx doing runtime alignment to REQUIRED_ALIGN on TARGET. */
|
||
|
||
rtx
|
||
align_dynamic_address (rtx target, unsigned required_align)
|
||
{
|
||
/* CEIL_DIV_EXPR needs to worry about the addition overflowing,
|
||
but we know it can't. So add ourselves and then do
|
||
TRUNC_DIV_EXPR. */
|
||
target = expand_binop (Pmode, add_optab, target,
|
||
gen_int_mode (required_align / BITS_PER_UNIT - 1,
|
||
Pmode),
|
||
NULL_RTX, 1, OPTAB_LIB_WIDEN);
|
||
target = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, target,
|
||
gen_int_mode (required_align / BITS_PER_UNIT,
|
||
Pmode),
|
||
NULL_RTX, 1);
|
||
target = expand_mult (Pmode, target,
|
||
gen_int_mode (required_align / BITS_PER_UNIT,
|
||
Pmode),
|
||
NULL_RTX, 1);
|
||
|
||
return target;
|
||
}
|
||
|
||
/* Return an rtx through *PSIZE, representing the size of an area of memory to
|
||
be dynamically pushed on the stack.
|
||
|
||
*PSIZE is an rtx representing the size of the area.
|
||
|
||
SIZE_ALIGN is the alignment (in bits) that we know SIZE has. This
|
||
parameter may be zero. If so, a proper value will be extracted
|
||
from SIZE if it is constant, otherwise BITS_PER_UNIT will be assumed.
|
||
|
||
REQUIRED_ALIGN is the alignment (in bits) required for the region
|
||
of memory.
|
||
|
||
If PSTACK_USAGE_SIZE is not NULL it points to a value that is increased for
|
||
the additional size returned. */
|
||
void
|
||
get_dynamic_stack_size (rtx *psize, unsigned size_align,
|
||
unsigned required_align,
|
||
HOST_WIDE_INT *pstack_usage_size)
|
||
{
|
||
rtx size = *psize;
|
||
|
||
/* Ensure the size is in the proper mode. */
|
||
if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
|
||
size = convert_to_mode (Pmode, size, 1);
|
||
|
||
if (CONST_INT_P (size))
|
||
{
|
||
unsigned HOST_WIDE_INT lsb;
|
||
|
||
lsb = INTVAL (size);
|
||
lsb &= -lsb;
|
||
|
||
/* Watch out for overflow truncating to "unsigned". */
|
||
if (lsb > UINT_MAX / BITS_PER_UNIT)
|
||
size_align = 1u << (HOST_BITS_PER_INT - 1);
|
||
else
|
||
size_align = (unsigned)lsb * BITS_PER_UNIT;
|
||
}
|
||
else if (size_align < BITS_PER_UNIT)
|
||
size_align = BITS_PER_UNIT;
|
||
|
||
/* We can't attempt to minimize alignment necessary, because we don't
|
||
know the final value of preferred_stack_boundary yet while executing
|
||
this code. */
|
||
if (crtl->preferred_stack_boundary < PREFERRED_STACK_BOUNDARY)
|
||
crtl->preferred_stack_boundary = PREFERRED_STACK_BOUNDARY;
|
||
|
||
/* We will need to ensure that the address we return is aligned to
|
||
REQUIRED_ALIGN. At this point in the compilation, we don't always
|
||
know the final value of the STACK_DYNAMIC_OFFSET used in function.cc
|
||
(it might depend on the size of the outgoing parameter lists, for
|
||
example), so we must preventively align the value. We leave space
|
||
in SIZE for the hole that might result from the alignment operation. */
|
||
|
||
unsigned known_align = REGNO_POINTER_ALIGN (VIRTUAL_STACK_DYNAMIC_REGNUM);
|
||
if (known_align == 0)
|
||
known_align = BITS_PER_UNIT;
|
||
if (required_align > known_align)
|
||
{
|
||
unsigned extra = (required_align - known_align) / BITS_PER_UNIT;
|
||
size = plus_constant (Pmode, size, extra);
|
||
size = force_operand (size, NULL_RTX);
|
||
if (size_align > known_align)
|
||
size_align = known_align;
|
||
|
||
if (flag_stack_usage_info && pstack_usage_size)
|
||
*pstack_usage_size += extra;
|
||
}
|
||
|
||
/* Round the size to a multiple of the required stack alignment.
|
||
Since the stack is presumed to be rounded before this allocation,
|
||
this will maintain the required alignment.
|
||
|
||
If the stack grows downward, we could save an insn by subtracting
|
||
SIZE from the stack pointer and then aligning the stack pointer.
|
||
The problem with this is that the stack pointer may be unaligned
|
||
between the execution of the subtraction and alignment insns and
|
||
some machines do not allow this. Even on those that do, some
|
||
signal handlers malfunction if a signal should occur between those
|
||
insns. Since this is an extremely rare event, we have no reliable
|
||
way of knowing which systems have this problem. So we avoid even
|
||
momentarily mis-aligning the stack. */
|
||
if (size_align % MAX_SUPPORTED_STACK_ALIGNMENT != 0)
|
||
{
|
||
size = round_push (size);
|
||
|
||
if (flag_stack_usage_info && pstack_usage_size)
|
||
{
|
||
int align = crtl->preferred_stack_boundary / BITS_PER_UNIT;
|
||
*pstack_usage_size =
|
||
(*pstack_usage_size + align - 1) / align * align;
|
||
}
|
||
}
|
||
|
||
*psize = size;
|
||
}
|
||
|
||
/* Return the number of bytes to "protect" on the stack for -fstack-check.
|
||
|
||
"protect" in the context of -fstack-check means how many bytes we need
|
||
to always ensure are available on the stack; as a consequence, this is
|
||
also how many bytes are first skipped when probing the stack.
|
||
|
||
On some targets we want to reuse the -fstack-check prologue support
|
||
to give a degree of protection against stack clashing style attacks.
|
||
|
||
In that scenario we do not want to skip bytes before probing as that
|
||
would render the stack clash protections useless.
|
||
|
||
So we never use STACK_CHECK_PROTECT directly. Instead we indirectly
|
||
use it through this helper, which allows to provide different values
|
||
for -fstack-check and -fstack-clash-protection. */
|
||
|
||
HOST_WIDE_INT
|
||
get_stack_check_protect (void)
|
||
{
|
||
if (flag_stack_clash_protection)
|
||
return 0;
|
||
|
||
return STACK_CHECK_PROTECT;
|
||
}
|
||
|
||
/* Return an rtx representing the address of an area of memory dynamically
|
||
pushed on the stack.
|
||
|
||
Any required stack pointer alignment is preserved.
|
||
|
||
SIZE is an rtx representing the size of the area.
|
||
|
||
SIZE_ALIGN is the alignment (in bits) that we know SIZE has. This
|
||
parameter may be zero. If so, a proper value will be extracted
|
||
from SIZE if it is constant, otherwise BITS_PER_UNIT will be assumed.
|
||
|
||
REQUIRED_ALIGN is the alignment (in bits) required for the region
|
||
of memory.
|
||
|
||
MAX_SIZE is an upper bound for SIZE, if SIZE is not constant, or -1 if
|
||
no such upper bound is known.
|
||
|
||
If CANNOT_ACCUMULATE is set to TRUE, the caller guarantees that the
|
||
stack space allocated by the generated code cannot be added with itself
|
||
in the course of the execution of the function. It is always safe to
|
||
pass FALSE here and the following criterion is sufficient in order to
|
||
pass TRUE: every path in the CFG that starts at the allocation point and
|
||
loops to it executes the associated deallocation code. */
|
||
|
||
rtx
|
||
allocate_dynamic_stack_space (rtx size, unsigned size_align,
|
||
unsigned required_align,
|
||
HOST_WIDE_INT max_size,
|
||
bool cannot_accumulate)
|
||
{
|
||
HOST_WIDE_INT stack_usage_size = -1;
|
||
rtx_code_label *final_label;
|
||
rtx final_target, target;
|
||
|
||
/* If we're asking for zero bytes, it doesn't matter what we point
|
||
to since we can't dereference it. But return a reasonable
|
||
address anyway. */
|
||
if (size == const0_rtx)
|
||
return virtual_stack_dynamic_rtx;
|
||
|
||
/* Otherwise, show we're calling alloca or equivalent. */
|
||
cfun->calls_alloca = 1;
|
||
|
||
/* If stack usage info is requested, look into the size we are passed.
|
||
We need to do so this early to avoid the obfuscation that may be
|
||
introduced later by the various alignment operations. */
|
||
if (flag_stack_usage_info)
|
||
{
|
||
if (CONST_INT_P (size))
|
||
stack_usage_size = INTVAL (size);
|
||
else if (REG_P (size))
|
||
{
|
||
/* Look into the last emitted insn and see if we can deduce
|
||
something for the register. */
|
||
rtx_insn *insn;
|
||
rtx set, note;
|
||
insn = get_last_insn ();
|
||
if ((set = single_set (insn)) && rtx_equal_p (SET_DEST (set), size))
|
||
{
|
||
if (CONST_INT_P (SET_SRC (set)))
|
||
stack_usage_size = INTVAL (SET_SRC (set));
|
||
else if ((note = find_reg_equal_equiv_note (insn))
|
||
&& CONST_INT_P (XEXP (note, 0)))
|
||
stack_usage_size = INTVAL (XEXP (note, 0));
|
||
}
|
||
}
|
||
|
||
/* If the size is not constant, try the maximum size. */
|
||
if (stack_usage_size < 0)
|
||
stack_usage_size = max_size;
|
||
|
||
/* If the size is still not constant, we can't say anything. */
|
||
if (stack_usage_size < 0)
|
||
{
|
||
current_function_has_unbounded_dynamic_stack_size = 1;
|
||
stack_usage_size = 0;
|
||
}
|
||
}
|
||
|
||
get_dynamic_stack_size (&size, size_align, required_align, &stack_usage_size);
|
||
|
||
target = gen_reg_rtx (Pmode);
|
||
|
||
/* The size is supposed to be fully adjusted at this point so record it
|
||
if stack usage info is requested. */
|
||
if (flag_stack_usage_info)
|
||
{
|
||
current_function_dynamic_stack_size += stack_usage_size;
|
||
|
||
/* ??? This is gross but the only safe stance in the absence
|
||
of stack usage oriented flow analysis. */
|
||
if (!cannot_accumulate)
|
||
current_function_has_unbounded_dynamic_stack_size = 1;
|
||
}
|
||
|
||
do_pending_stack_adjust ();
|
||
|
||
final_label = NULL;
|
||
final_target = NULL_RTX;
|
||
|
||
/* If we are splitting the stack, we need to ask the backend whether
|
||
there is enough room on the current stack. If there isn't, or if
|
||
the backend doesn't know how to tell is, then we need to call a
|
||
function to allocate memory in some other way. This memory will
|
||
be released when we release the current stack segment. The
|
||
effect is that stack allocation becomes less efficient, but at
|
||
least it doesn't cause a stack overflow. */
|
||
if (flag_split_stack)
|
||
{
|
||
rtx_code_label *available_label;
|
||
rtx ask, space, func;
|
||
|
||
available_label = NULL;
|
||
|
||
if (targetm.have_split_stack_space_check ())
|
||
{
|
||
available_label = gen_label_rtx ();
|
||
|
||
/* This instruction will branch to AVAILABLE_LABEL if there
|
||
are SIZE bytes available on the stack. */
|
||
emit_insn (targetm.gen_split_stack_space_check
|
||
(size, available_label));
|
||
}
|
||
|
||
/* The __morestack_allocate_stack_space function will allocate
|
||
memory using malloc. If the alignment of the memory returned
|
||
by malloc does not meet REQUIRED_ALIGN, we increase SIZE to
|
||
make sure we allocate enough space. */
|
||
if (MALLOC_ABI_ALIGNMENT >= required_align)
|
||
ask = size;
|
||
else
|
||
ask = expand_binop (Pmode, add_optab, size,
|
||
gen_int_mode (required_align / BITS_PER_UNIT - 1,
|
||
Pmode),
|
||
NULL_RTX, 1, OPTAB_LIB_WIDEN);
|
||
|
||
func = init_one_libfunc ("__morestack_allocate_stack_space");
|
||
|
||
space = emit_library_call_value (func, target, LCT_NORMAL, Pmode,
|
||
ask, Pmode);
|
||
|
||
if (available_label == NULL_RTX)
|
||
return space;
|
||
|
||
final_target = gen_reg_rtx (Pmode);
|
||
|
||
emit_move_insn (final_target, space);
|
||
|
||
final_label = gen_label_rtx ();
|
||
emit_jump (final_label);
|
||
|
||
emit_label (available_label);
|
||
}
|
||
|
||
/* We ought to be called always on the toplevel and stack ought to be aligned
|
||
properly. */
|
||
gcc_assert (multiple_p (stack_pointer_delta,
|
||
PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT));
|
||
|
||
/* If needed, check that we have the required amount of stack. Take into
|
||
account what has already been checked. */
|
||
if (STACK_CHECK_MOVING_SP)
|
||
;
|
||
else if (flag_stack_check == GENERIC_STACK_CHECK)
|
||
probe_stack_range (STACK_OLD_CHECK_PROTECT + STACK_CHECK_MAX_FRAME_SIZE,
|
||
size);
|
||
else if (flag_stack_check == STATIC_BUILTIN_STACK_CHECK)
|
||
probe_stack_range (get_stack_check_protect (), size);
|
||
|
||
/* Don't let anti_adjust_stack emit notes. */
|
||
suppress_reg_args_size = true;
|
||
|
||
/* Perform the required allocation from the stack. Some systems do
|
||
this differently than simply incrementing/decrementing from the
|
||
stack pointer, such as acquiring the space by calling malloc(). */
|
||
if (targetm.have_allocate_stack ())
|
||
{
|
||
class expand_operand ops[2];
|
||
/* We don't have to check against the predicate for operand 0 since
|
||
TARGET is known to be a pseudo of the proper mode, which must
|
||
be valid for the operand. */
|
||
create_fixed_operand (&ops[0], target);
|
||
create_convert_operand_to (&ops[1], size, STACK_SIZE_MODE, true);
|
||
expand_insn (targetm.code_for_allocate_stack, 2, ops);
|
||
}
|
||
else
|
||
{
|
||
poly_int64 saved_stack_pointer_delta;
|
||
|
||
if (!STACK_GROWS_DOWNWARD)
|
||
emit_move_insn (target, virtual_stack_dynamic_rtx);
|
||
|
||
/* Check stack bounds if necessary. */
|
||
if (crtl->limit_stack)
|
||
{
|
||
rtx available;
|
||
rtx_code_label *space_available = gen_label_rtx ();
|
||
if (STACK_GROWS_DOWNWARD)
|
||
available = expand_binop (Pmode, sub_optab,
|
||
stack_pointer_rtx, stack_limit_rtx,
|
||
NULL_RTX, 1, OPTAB_WIDEN);
|
||
else
|
||
available = expand_binop (Pmode, sub_optab,
|
||
stack_limit_rtx, stack_pointer_rtx,
|
||
NULL_RTX, 1, OPTAB_WIDEN);
|
||
|
||
emit_cmp_and_jump_insns (available, size, GEU, NULL_RTX, Pmode, 1,
|
||
space_available);
|
||
if (targetm.have_trap ())
|
||
emit_insn (targetm.gen_trap ());
|
||
else
|
||
error ("stack limits not supported on this target");
|
||
emit_barrier ();
|
||
emit_label (space_available);
|
||
}
|
||
|
||
saved_stack_pointer_delta = stack_pointer_delta;
|
||
|
||
/* If stack checking or stack clash protection is requested,
|
||
then probe the stack while allocating space from it. */
|
||
if (flag_stack_check && STACK_CHECK_MOVING_SP)
|
||
anti_adjust_stack_and_probe (size, false);
|
||
else if (flag_stack_clash_protection)
|
||
anti_adjust_stack_and_probe_stack_clash (size);
|
||
else
|
||
anti_adjust_stack (size);
|
||
|
||
/* Even if size is constant, don't modify stack_pointer_delta.
|
||
The constant size alloca should preserve
|
||
crtl->preferred_stack_boundary alignment. */
|
||
stack_pointer_delta = saved_stack_pointer_delta;
|
||
|
||
if (STACK_GROWS_DOWNWARD)
|
||
emit_move_insn (target, virtual_stack_dynamic_rtx);
|
||
}
|
||
|
||
suppress_reg_args_size = false;
|
||
|
||
/* Finish up the split stack handling. */
|
||
if (final_label != NULL_RTX)
|
||
{
|
||
gcc_assert (flag_split_stack);
|
||
emit_move_insn (final_target, target);
|
||
emit_label (final_label);
|
||
target = final_target;
|
||
}
|
||
|
||
target = align_dynamic_address (target, required_align);
|
||
|
||
/* Now that we've committed to a return value, mark its alignment. */
|
||
mark_reg_pointer (target, required_align);
|
||
|
||
/* Record the new stack level. */
|
||
record_new_stack_level ();
|
||
|
||
return target;
|
||
}
|
||
|
||
/* Return an rtx representing the address of an area of memory already
|
||
statically pushed onto the stack in the virtual stack vars area. (It is
|
||
assumed that the area is allocated in the function prologue.)
|
||
|
||
Any required stack pointer alignment is preserved.
|
||
|
||
OFFSET is the offset of the area into the virtual stack vars area.
|
||
|
||
REQUIRED_ALIGN is the alignment (in bits) required for the region
|
||
of memory.
|
||
|
||
BASE is the rtx of the base of this virtual stack vars area.
|
||
The only time this is not `virtual_stack_vars_rtx` is when tagging pointers
|
||
on the stack. */
|
||
|
||
rtx
|
||
get_dynamic_stack_base (poly_int64 offset, unsigned required_align, rtx base)
|
||
{
|
||
rtx target;
|
||
|
||
if (crtl->preferred_stack_boundary < PREFERRED_STACK_BOUNDARY)
|
||
crtl->preferred_stack_boundary = PREFERRED_STACK_BOUNDARY;
|
||
|
||
target = gen_reg_rtx (Pmode);
|
||
emit_move_insn (target, base);
|
||
target = expand_binop (Pmode, add_optab, target,
|
||
gen_int_mode (offset, Pmode),
|
||
NULL_RTX, 1, OPTAB_LIB_WIDEN);
|
||
target = align_dynamic_address (target, required_align);
|
||
|
||
/* Now that we've committed to a return value, mark its alignment. */
|
||
mark_reg_pointer (target, required_align);
|
||
|
||
return target;
|
||
}
|
||
|
||
/* A front end may want to override GCC's stack checking by providing a
|
||
run-time routine to call to check the stack, so provide a mechanism for
|
||
calling that routine. */
|
||
|
||
static GTY(()) rtx stack_check_libfunc;
|
||
|
||
void
|
||
set_stack_check_libfunc (const char *libfunc_name)
|
||
{
|
||
gcc_assert (stack_check_libfunc == NULL_RTX);
|
||
stack_check_libfunc = gen_rtx_SYMBOL_REF (Pmode, libfunc_name);
|
||
tree ptype
|
||
= Pmode == ptr_mode
|
||
? ptr_type_node
|
||
: lang_hooks.types.type_for_mode (Pmode, 1);
|
||
tree ftype
|
||
= build_function_type_list (void_type_node, ptype, NULL_TREE);
|
||
tree decl = build_decl (UNKNOWN_LOCATION, FUNCTION_DECL,
|
||
get_identifier (libfunc_name), ftype);
|
||
DECL_EXTERNAL (decl) = 1;
|
||
SET_SYMBOL_REF_DECL (stack_check_libfunc, decl);
|
||
}
|
||
|
||
/* Emit one stack probe at ADDRESS, an address within the stack. */
|
||
|
||
void
|
||
emit_stack_probe (rtx address)
|
||
{
|
||
if (targetm.have_probe_stack_address ())
|
||
{
|
||
class expand_operand ops[1];
|
||
insn_code icode = targetm.code_for_probe_stack_address;
|
||
create_address_operand (ops, address);
|
||
maybe_legitimize_operands (icode, 0, 1, ops);
|
||
expand_insn (icode, 1, ops);
|
||
}
|
||
else
|
||
{
|
||
rtx memref = gen_rtx_MEM (word_mode, address);
|
||
|
||
MEM_VOLATILE_P (memref) = 1;
|
||
memref = validize_mem (memref);
|
||
|
||
/* See if we have an insn to probe the stack. */
|
||
if (targetm.have_probe_stack ())
|
||
emit_insn (targetm.gen_probe_stack (memref));
|
||
else
|
||
emit_move_insn (memref, const0_rtx);
|
||
}
|
||
}
|
||
|
||
/* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
|
||
FIRST is a constant and size is a Pmode RTX. These are offsets from
|
||
the current stack pointer. STACK_GROWS_DOWNWARD says whether to add
|
||
or subtract them from the stack pointer. */
|
||
|
||
#define PROBE_INTERVAL (1 << STACK_CHECK_PROBE_INTERVAL_EXP)
|
||
|
||
#if STACK_GROWS_DOWNWARD
|
||
#define STACK_GROW_OP MINUS
|
||
#define STACK_GROW_OPTAB sub_optab
|
||
#define STACK_GROW_OFF(off) -(off)
|
||
#else
|
||
#define STACK_GROW_OP PLUS
|
||
#define STACK_GROW_OPTAB add_optab
|
||
#define STACK_GROW_OFF(off) (off)
|
||
#endif
|
||
|
||
void
|
||
probe_stack_range (HOST_WIDE_INT first, rtx size)
|
||
{
|
||
/* First ensure SIZE is Pmode. */
|
||
if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
|
||
size = convert_to_mode (Pmode, size, 1);
|
||
|
||
/* Next see if we have a function to check the stack. */
|
||
if (stack_check_libfunc)
|
||
{
|
||
rtx addr = memory_address (Pmode,
|
||
gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
|
||
stack_pointer_rtx,
|
||
plus_constant (Pmode,
|
||
size, first)));
|
||
emit_library_call (stack_check_libfunc, LCT_THROW, VOIDmode,
|
||
addr, Pmode);
|
||
}
|
||
|
||
/* Next see if we have an insn to check the stack. */
|
||
else if (targetm.have_check_stack ())
|
||
{
|
||
class expand_operand ops[1];
|
||
rtx addr = memory_address (Pmode,
|
||
gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
|
||
stack_pointer_rtx,
|
||
plus_constant (Pmode,
|
||
size, first)));
|
||
bool success;
|
||
create_input_operand (&ops[0], addr, Pmode);
|
||
success = maybe_expand_insn (targetm.code_for_check_stack, 1, ops);
|
||
gcc_assert (success);
|
||
}
|
||
|
||
/* Otherwise we have to generate explicit probes. If we have a constant
|
||
small number of them to generate, that's the easy case. */
|
||
else if (CONST_INT_P (size) && INTVAL (size) < 7 * PROBE_INTERVAL)
|
||
{
|
||
HOST_WIDE_INT isize = INTVAL (size), i;
|
||
rtx addr;
|
||
|
||
/* Probe at FIRST + N * PROBE_INTERVAL for values of N from 1 until
|
||
it exceeds SIZE. If only one probe is needed, this will not
|
||
generate any code. Then probe at FIRST + SIZE. */
|
||
for (i = PROBE_INTERVAL; i < isize; i += PROBE_INTERVAL)
|
||
{
|
||
addr = memory_address (Pmode,
|
||
plus_constant (Pmode, stack_pointer_rtx,
|
||
STACK_GROW_OFF (first + i)));
|
||
emit_stack_probe (addr);
|
||
}
|
||
|
||
addr = memory_address (Pmode,
|
||
plus_constant (Pmode, stack_pointer_rtx,
|
||
STACK_GROW_OFF (first + isize)));
|
||
emit_stack_probe (addr);
|
||
}
|
||
|
||
/* In the variable case, do the same as above, but in a loop. Note that we
|
||
must be extra careful with variables wrapping around because we might be
|
||
at the very top (or the very bottom) of the address space and we have to
|
||
be able to handle this case properly; in particular, we use an equality
|
||
test for the loop condition. */
|
||
else
|
||
{
|
||
rtx rounded_size, rounded_size_op, test_addr, last_addr, temp;
|
||
rtx_code_label *loop_lab = gen_label_rtx ();
|
||
rtx_code_label *end_lab = gen_label_rtx ();
|
||
|
||
/* Step 1: round SIZE to the previous multiple of the interval. */
|
||
|
||
/* ROUNDED_SIZE = SIZE & -PROBE_INTERVAL */
|
||
rounded_size
|
||
= simplify_gen_binary (AND, Pmode, size,
|
||
gen_int_mode (-PROBE_INTERVAL, Pmode));
|
||
rounded_size_op = force_operand (rounded_size, NULL_RTX);
|
||
|
||
|
||
/* Step 2: compute initial and final value of the loop counter. */
|
||
|
||
/* TEST_ADDR = SP + FIRST. */
|
||
test_addr = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
|
||
stack_pointer_rtx,
|
||
gen_int_mode (first, Pmode)),
|
||
NULL_RTX);
|
||
|
||
/* LAST_ADDR = SP + FIRST + ROUNDED_SIZE. */
|
||
last_addr = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
|
||
test_addr,
|
||
rounded_size_op), NULL_RTX);
|
||
|
||
|
||
/* Step 3: the loop
|
||
|
||
while (TEST_ADDR != LAST_ADDR)
|
||
{
|
||
TEST_ADDR = TEST_ADDR + PROBE_INTERVAL
|
||
probe at TEST_ADDR
|
||
}
|
||
|
||
probes at FIRST + N * PROBE_INTERVAL for values of N from 1
|
||
until it is equal to ROUNDED_SIZE. */
|
||
|
||
emit_label (loop_lab);
|
||
|
||
/* Jump to END_LAB if TEST_ADDR == LAST_ADDR. */
|
||
emit_cmp_and_jump_insns (test_addr, last_addr, EQ, NULL_RTX, Pmode, 1,
|
||
end_lab);
|
||
|
||
/* TEST_ADDR = TEST_ADDR + PROBE_INTERVAL. */
|
||
temp = expand_binop (Pmode, STACK_GROW_OPTAB, test_addr,
|
||
gen_int_mode (PROBE_INTERVAL, Pmode), test_addr,
|
||
1, OPTAB_WIDEN);
|
||
|
||
gcc_assert (temp == test_addr);
|
||
|
||
/* Probe at TEST_ADDR. */
|
||
emit_stack_probe (test_addr);
|
||
|
||
emit_jump (loop_lab);
|
||
|
||
emit_label (end_lab);
|
||
|
||
|
||
/* Step 4: probe at FIRST + SIZE if we cannot assert at compile-time
|
||
that SIZE is equal to ROUNDED_SIZE. */
|
||
|
||
/* TEMP = SIZE - ROUNDED_SIZE. */
|
||
temp = simplify_gen_binary (MINUS, Pmode, size, rounded_size);
|
||
if (temp != const0_rtx)
|
||
{
|
||
rtx addr;
|
||
|
||
if (CONST_INT_P (temp))
|
||
{
|
||
/* Use [base + disp} addressing mode if supported. */
|
||
HOST_WIDE_INT offset = INTVAL (temp);
|
||
addr = memory_address (Pmode,
|
||
plus_constant (Pmode, last_addr,
|
||
STACK_GROW_OFF (offset)));
|
||
}
|
||
else
|
||
{
|
||
/* Manual CSE if the difference is not known at compile-time. */
|
||
temp = gen_rtx_MINUS (Pmode, size, rounded_size_op);
|
||
addr = memory_address (Pmode,
|
||
gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
|
||
last_addr, temp));
|
||
}
|
||
|
||
emit_stack_probe (addr);
|
||
}
|
||
}
|
||
|
||
/* Make sure nothing is scheduled before we are done. */
|
||
emit_insn (gen_blockage ());
|
||
}
|
||
|
||
/* Compute parameters for stack clash probing a dynamic stack
|
||
allocation of SIZE bytes.
|
||
|
||
We compute ROUNDED_SIZE, LAST_ADDR, RESIDUAL and PROBE_INTERVAL.
|
||
|
||
Additionally we conditionally dump the type of probing that will
|
||
be needed given the values computed. */
|
||
|
||
void
|
||
compute_stack_clash_protection_loop_data (rtx *rounded_size, rtx *last_addr,
|
||
rtx *residual,
|
||
HOST_WIDE_INT *probe_interval,
|
||
rtx size)
|
||
{
|
||
/* Round SIZE down to STACK_CLASH_PROTECTION_PROBE_INTERVAL */
|
||
*probe_interval
|
||
= 1 << param_stack_clash_protection_probe_interval;
|
||
*rounded_size = simplify_gen_binary (AND, Pmode, size,
|
||
GEN_INT (-*probe_interval));
|
||
|
||
/* Compute the value of the stack pointer for the last iteration.
|
||
It's just SP + ROUNDED_SIZE. */
|
||
rtx rounded_size_op = force_operand (*rounded_size, NULL_RTX);
|
||
*last_addr = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
|
||
stack_pointer_rtx,
|
||
rounded_size_op),
|
||
NULL_RTX);
|
||
|
||
/* Compute any residuals not allocated by the loop above. Residuals
|
||
are just the ROUNDED_SIZE - SIZE. */
|
||
*residual = simplify_gen_binary (MINUS, Pmode, size, *rounded_size);
|
||
|
||
/* Dump key information to make writing tests easy. */
|
||
if (dump_file)
|
||
{
|
||
if (*rounded_size == CONST0_RTX (Pmode))
|
||
fprintf (dump_file,
|
||
"Stack clash skipped dynamic allocation and probing loop.\n");
|
||
else if (CONST_INT_P (*rounded_size)
|
||
&& INTVAL (*rounded_size) <= 4 * *probe_interval)
|
||
fprintf (dump_file,
|
||
"Stack clash dynamic allocation and probing inline.\n");
|
||
else if (CONST_INT_P (*rounded_size))
|
||
fprintf (dump_file,
|
||
"Stack clash dynamic allocation and probing in "
|
||
"rotated loop.\n");
|
||
else
|
||
fprintf (dump_file,
|
||
"Stack clash dynamic allocation and probing in loop.\n");
|
||
|
||
if (*residual != CONST0_RTX (Pmode))
|
||
fprintf (dump_file,
|
||
"Stack clash dynamic allocation and probing residuals.\n");
|
||
else
|
||
fprintf (dump_file,
|
||
"Stack clash skipped dynamic allocation and "
|
||
"probing residuals.\n");
|
||
}
|
||
}
|
||
|
||
/* Emit the start of an allocate/probe loop for stack
|
||
clash protection.
|
||
|
||
LOOP_LAB and END_LAB are returned for use when we emit the
|
||
end of the loop.
|
||
|
||
LAST addr is the value for SP which stops the loop. */
|
||
void
|
||
emit_stack_clash_protection_probe_loop_start (rtx *loop_lab,
|
||
rtx *end_lab,
|
||
rtx last_addr,
|
||
bool rotated)
|
||
{
|
||
/* Essentially we want to emit any setup code, the top of loop
|
||
label and the comparison at the top of the loop. */
|
||
*loop_lab = gen_label_rtx ();
|
||
*end_lab = gen_label_rtx ();
|
||
|
||
emit_label (*loop_lab);
|
||
if (!rotated)
|
||
emit_cmp_and_jump_insns (stack_pointer_rtx, last_addr, EQ, NULL_RTX,
|
||
Pmode, 1, *end_lab);
|
||
}
|
||
|
||
/* Emit the end of a stack clash probing loop.
|
||
|
||
This consists of just the jump back to LOOP_LAB and
|
||
emitting END_LOOP after the loop. */
|
||
|
||
void
|
||
emit_stack_clash_protection_probe_loop_end (rtx loop_lab, rtx end_loop,
|
||
rtx last_addr, bool rotated)
|
||
{
|
||
if (rotated)
|
||
emit_cmp_and_jump_insns (stack_pointer_rtx, last_addr, NE, NULL_RTX,
|
||
Pmode, 1, loop_lab);
|
||
else
|
||
emit_jump (loop_lab);
|
||
|
||
emit_label (end_loop);
|
||
|
||
}
|
||
|
||
/* Adjust the stack pointer by minus SIZE (an rtx for a number of bytes)
|
||
while probing it. This pushes when SIZE is positive. SIZE need not
|
||
be constant.
|
||
|
||
This is subtly different than anti_adjust_stack_and_probe to try and
|
||
prevent stack-clash attacks
|
||
|
||
1. It must assume no knowledge of the probing state, any allocation
|
||
must probe.
|
||
|
||
Consider the case of a 1 byte alloca in a loop. If the sum of the
|
||
allocations is large, then this could be used to jump the guard if
|
||
probes were not emitted.
|
||
|
||
2. It never skips probes, whereas anti_adjust_stack_and_probe will
|
||
skip the probe on the first PROBE_INTERVAL on the assumption it
|
||
was already done in the prologue and in previous allocations.
|
||
|
||
3. It only allocates and probes SIZE bytes, it does not need to
|
||
allocate/probe beyond that because this probing style does not
|
||
guarantee signal handling capability if the guard is hit. */
|
||
|
||
void
|
||
anti_adjust_stack_and_probe_stack_clash (rtx size)
|
||
{
|
||
/* First ensure SIZE is Pmode. */
|
||
if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
|
||
size = convert_to_mode (Pmode, size, 1);
|
||
|
||
/* We can get here with a constant size on some targets. */
|
||
rtx rounded_size, last_addr, residual;
|
||
HOST_WIDE_INT probe_interval, probe_range;
|
||
bool target_probe_range_p = false;
|
||
compute_stack_clash_protection_loop_data (&rounded_size, &last_addr,
|
||
&residual, &probe_interval, size);
|
||
|
||
/* Get the back-end specific probe ranges. */
|
||
probe_range = targetm.stack_clash_protection_alloca_probe_range ();
|
||
target_probe_range_p = probe_range != 0;
|
||
gcc_assert (probe_range >= 0);
|
||
|
||
/* If no back-end specific range defined, default to the top of the newly
|
||
allocated range. */
|
||
if (probe_range == 0)
|
||
probe_range = probe_interval - GET_MODE_SIZE (word_mode);
|
||
|
||
if (rounded_size != CONST0_RTX (Pmode))
|
||
{
|
||
if (CONST_INT_P (rounded_size)
|
||
&& INTVAL (rounded_size) <= 4 * probe_interval)
|
||
{
|
||
for (HOST_WIDE_INT i = 0;
|
||
i < INTVAL (rounded_size);
|
||
i += probe_interval)
|
||
{
|
||
anti_adjust_stack (GEN_INT (probe_interval));
|
||
/* The prologue does not probe residuals. Thus the offset
|
||
here to probe just beyond what the prologue had already
|
||
allocated. */
|
||
emit_stack_probe (plus_constant (Pmode, stack_pointer_rtx,
|
||
probe_range));
|
||
|
||
emit_insn (gen_blockage ());
|
||
}
|
||
}
|
||
else
|
||
{
|
||
rtx loop_lab, end_loop;
|
||
bool rotate_loop = CONST_INT_P (rounded_size);
|
||
emit_stack_clash_protection_probe_loop_start (&loop_lab, &end_loop,
|
||
last_addr, rotate_loop);
|
||
|
||
anti_adjust_stack (GEN_INT (probe_interval));
|
||
|
||
/* The prologue does not probe residuals. Thus the offset here
|
||
to probe just beyond what the prologue had already
|
||
allocated. */
|
||
emit_stack_probe (plus_constant (Pmode, stack_pointer_rtx,
|
||
probe_range));
|
||
|
||
emit_stack_clash_protection_probe_loop_end (loop_lab, end_loop,
|
||
last_addr, rotate_loop);
|
||
emit_insn (gen_blockage ());
|
||
}
|
||
}
|
||
|
||
if (residual != CONST0_RTX (Pmode))
|
||
{
|
||
rtx label = NULL_RTX;
|
||
/* RESIDUAL could be zero at runtime and in that case *sp could
|
||
hold live data. Furthermore, we do not want to probe into the
|
||
red zone.
|
||
|
||
If TARGET_PROBE_RANGE_P then the target has promised it's safe to
|
||
probe at offset 0. In which case we no longer have to check for
|
||
RESIDUAL == 0. However we still need to probe at the right offset
|
||
when RESIDUAL > PROBE_RANGE, in which case we probe at PROBE_RANGE.
|
||
|
||
If !TARGET_PROBE_RANGE_P then go ahead and just guard the probe at *sp
|
||
on RESIDUAL != 0 at runtime if RESIDUAL is not a compile time constant.
|
||
*/
|
||
anti_adjust_stack (residual);
|
||
|
||
if (!CONST_INT_P (residual))
|
||
{
|
||
label = gen_label_rtx ();
|
||
rtx_code op = target_probe_range_p ? LT : EQ;
|
||
rtx probe_cmp_value = target_probe_range_p
|
||
? gen_rtx_CONST_INT (GET_MODE (residual), probe_range)
|
||
: CONST0_RTX (GET_MODE (residual));
|
||
|
||
if (target_probe_range_p)
|
||
emit_stack_probe (stack_pointer_rtx);
|
||
|
||
emit_cmp_and_jump_insns (residual, probe_cmp_value,
|
||
op, NULL_RTX, Pmode, 1, label);
|
||
}
|
||
|
||
rtx x = NULL_RTX;
|
||
|
||
/* If RESIDUAL isn't a constant and TARGET_PROBE_RANGE_P then we probe up
|
||
by the ABI defined safe value. */
|
||
if (!CONST_INT_P (residual) && target_probe_range_p)
|
||
x = GEN_INT (probe_range);
|
||
/* If RESIDUAL is a constant but smaller than the ABI defined safe value,
|
||
we still want to probe up, but the safest amount if a word. */
|
||
else if (target_probe_range_p)
|
||
{
|
||
if (INTVAL (residual) <= probe_range)
|
||
x = GEN_INT (GET_MODE_SIZE (word_mode));
|
||
else
|
||
x = GEN_INT (probe_range);
|
||
}
|
||
else
|
||
/* If nothing else, probe at the top of the new allocation. */
|
||
x = plus_constant (Pmode, residual, -GET_MODE_SIZE (word_mode));
|
||
|
||
emit_stack_probe (gen_rtx_PLUS (Pmode, stack_pointer_rtx, x));
|
||
|
||
emit_insn (gen_blockage ());
|
||
if (!CONST_INT_P (residual))
|
||
emit_label (label);
|
||
}
|
||
}
|
||
|
||
|
||
/* Adjust the stack pointer by minus SIZE (an rtx for a number of bytes)
|
||
while probing it. This pushes when SIZE is positive. SIZE need not
|
||
be constant. If ADJUST_BACK is true, adjust back the stack pointer
|
||
by plus SIZE at the end. */
|
||
|
||
void
|
||
anti_adjust_stack_and_probe (rtx size, bool adjust_back)
|
||
{
|
||
/* We skip the probe for the first interval + a small dope of 4 words and
|
||
probe that many bytes past the specified size to maintain a protection
|
||
area at the botton of the stack. */
|
||
const int dope = 4 * UNITS_PER_WORD;
|
||
|
||
/* First ensure SIZE is Pmode. */
|
||
if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
|
||
size = convert_to_mode (Pmode, size, 1);
|
||
|
||
/* If we have a constant small number of probes to generate, that's the
|
||
easy case. */
|
||
if (CONST_INT_P (size) && INTVAL (size) < 7 * PROBE_INTERVAL)
|
||
{
|
||
HOST_WIDE_INT isize = INTVAL (size), i;
|
||
bool first_probe = true;
|
||
|
||
/* Adjust SP and probe at PROBE_INTERVAL + N * PROBE_INTERVAL for
|
||
values of N from 1 until it exceeds SIZE. If only one probe is
|
||
needed, this will not generate any code. Then adjust and probe
|
||
to PROBE_INTERVAL + SIZE. */
|
||
for (i = PROBE_INTERVAL; i < isize; i += PROBE_INTERVAL)
|
||
{
|
||
if (first_probe)
|
||
{
|
||
anti_adjust_stack (GEN_INT (2 * PROBE_INTERVAL + dope));
|
||
first_probe = false;
|
||
}
|
||
else
|
||
anti_adjust_stack (GEN_INT (PROBE_INTERVAL));
|
||
emit_stack_probe (stack_pointer_rtx);
|
||
}
|
||
|
||
if (first_probe)
|
||
anti_adjust_stack (plus_constant (Pmode, size, PROBE_INTERVAL + dope));
|
||
else
|
||
anti_adjust_stack (plus_constant (Pmode, size, PROBE_INTERVAL - i));
|
||
emit_stack_probe (stack_pointer_rtx);
|
||
}
|
||
|
||
/* In the variable case, do the same as above, but in a loop. Note that we
|
||
must be extra careful with variables wrapping around because we might be
|
||
at the very top (or the very bottom) of the address space and we have to
|
||
be able to handle this case properly; in particular, we use an equality
|
||
test for the loop condition. */
|
||
else
|
||
{
|
||
rtx rounded_size, rounded_size_op, last_addr, temp;
|
||
rtx_code_label *loop_lab = gen_label_rtx ();
|
||
rtx_code_label *end_lab = gen_label_rtx ();
|
||
|
||
|
||
/* Step 1: round SIZE to the previous multiple of the interval. */
|
||
|
||
/* ROUNDED_SIZE = SIZE & -PROBE_INTERVAL */
|
||
rounded_size
|
||
= simplify_gen_binary (AND, Pmode, size,
|
||
gen_int_mode (-PROBE_INTERVAL, Pmode));
|
||
rounded_size_op = force_operand (rounded_size, NULL_RTX);
|
||
|
||
|
||
/* Step 2: compute initial and final value of the loop counter. */
|
||
|
||
/* SP = SP_0 + PROBE_INTERVAL. */
|
||
anti_adjust_stack (GEN_INT (PROBE_INTERVAL + dope));
|
||
|
||
/* LAST_ADDR = SP_0 + PROBE_INTERVAL + ROUNDED_SIZE. */
|
||
last_addr = force_operand (gen_rtx_fmt_ee (STACK_GROW_OP, Pmode,
|
||
stack_pointer_rtx,
|
||
rounded_size_op), NULL_RTX);
|
||
|
||
|
||
/* Step 3: the loop
|
||
|
||
while (SP != LAST_ADDR)
|
||
{
|
||
SP = SP + PROBE_INTERVAL
|
||
probe at SP
|
||
}
|
||
|
||
adjusts SP and probes at PROBE_INTERVAL + N * PROBE_INTERVAL for
|
||
values of N from 1 until it is equal to ROUNDED_SIZE. */
|
||
|
||
emit_label (loop_lab);
|
||
|
||
/* Jump to END_LAB if SP == LAST_ADDR. */
|
||
emit_cmp_and_jump_insns (stack_pointer_rtx, last_addr, EQ, NULL_RTX,
|
||
Pmode, 1, end_lab);
|
||
|
||
/* SP = SP + PROBE_INTERVAL and probe at SP. */
|
||
anti_adjust_stack (GEN_INT (PROBE_INTERVAL));
|
||
emit_stack_probe (stack_pointer_rtx);
|
||
|
||
emit_jump (loop_lab);
|
||
|
||
emit_label (end_lab);
|
||
|
||
|
||
/* Step 4: adjust SP and probe at PROBE_INTERVAL + SIZE if we cannot
|
||
assert at compile-time that SIZE is equal to ROUNDED_SIZE. */
|
||
|
||
/* TEMP = SIZE - ROUNDED_SIZE. */
|
||
temp = simplify_gen_binary (MINUS, Pmode, size, rounded_size);
|
||
if (temp != const0_rtx)
|
||
{
|
||
/* Manual CSE if the difference is not known at compile-time. */
|
||
if (GET_CODE (temp) != CONST_INT)
|
||
temp = gen_rtx_MINUS (Pmode, size, rounded_size_op);
|
||
anti_adjust_stack (temp);
|
||
emit_stack_probe (stack_pointer_rtx);
|
||
}
|
||
}
|
||
|
||
/* Adjust back and account for the additional first interval. */
|
||
if (adjust_back)
|
||
adjust_stack (plus_constant (Pmode, size, PROBE_INTERVAL + dope));
|
||
else
|
||
adjust_stack (GEN_INT (PROBE_INTERVAL + dope));
|
||
}
|
||
|
||
/* Return an rtx representing the register or memory location
|
||
in which a scalar value of data type VALTYPE
|
||
was returned by a function call to function FUNC.
|
||
FUNC is a FUNCTION_DECL, FNTYPE a FUNCTION_TYPE node if the precise
|
||
function is known, otherwise 0.
|
||
OUTGOING is 1 if on a machine with register windows this function
|
||
should return the register in which the function will put its result
|
||
and 0 otherwise. */
|
||
|
||
rtx
|
||
hard_function_value (const_tree valtype, const_tree func, const_tree fntype,
|
||
int outgoing ATTRIBUTE_UNUSED)
|
||
{
|
||
rtx val;
|
||
|
||
val = targetm.calls.function_value (valtype, func ? func : fntype, outgoing);
|
||
|
||
if (REG_P (val)
|
||
&& GET_MODE (val) == BLKmode)
|
||
{
|
||
unsigned HOST_WIDE_INT bytes = arg_int_size_in_bytes (valtype);
|
||
opt_scalar_int_mode tmpmode;
|
||
|
||
/* int_size_in_bytes can return -1. We don't need a check here
|
||
since the value of bytes will then be large enough that no
|
||
mode will match anyway. */
|
||
|
||
FOR_EACH_MODE_IN_CLASS (tmpmode, MODE_INT)
|
||
{
|
||
/* Have we found a large enough mode? */
|
||
if (GET_MODE_SIZE (tmpmode.require ()) >= bytes)
|
||
break;
|
||
}
|
||
|
||
PUT_MODE (val, tmpmode.require ());
|
||
}
|
||
return val;
|
||
}
|
||
|
||
/* Return an rtx representing the register or memory location
|
||
in which a scalar value of mode MODE was returned by a library call. */
|
||
|
||
rtx
|
||
hard_libcall_value (machine_mode mode, rtx fun)
|
||
{
|
||
return targetm.calls.libcall_value (mode, fun);
|
||
}
|
||
|
||
/* Look up the tree code for a given rtx code
|
||
to provide the arithmetic operation for real_arithmetic.
|
||
The function returns an int because the caller may not know
|
||
what `enum tree_code' means. */
|
||
|
||
int
|
||
rtx_to_tree_code (enum rtx_code code)
|
||
{
|
||
enum tree_code tcode;
|
||
|
||
switch (code)
|
||
{
|
||
case PLUS:
|
||
tcode = PLUS_EXPR;
|
||
break;
|
||
case MINUS:
|
||
tcode = MINUS_EXPR;
|
||
break;
|
||
case MULT:
|
||
tcode = MULT_EXPR;
|
||
break;
|
||
case DIV:
|
||
tcode = RDIV_EXPR;
|
||
break;
|
||
case SMIN:
|
||
tcode = MIN_EXPR;
|
||
break;
|
||
case SMAX:
|
||
tcode = MAX_EXPR;
|
||
break;
|
||
default:
|
||
tcode = LAST_AND_UNUSED_TREE_CODE;
|
||
break;
|
||
}
|
||
return ((int) tcode);
|
||
}
|
||
|
||
#include "gt-explow.h"
|