| /* Subroutines for manipulating rtx's in semantically interesting ways. |
| Copyright (C) 1987-2021 Free Software Foundation, Inc. |
| |
| This file is part of GCC. |
| |
| GCC is free software; you can redistribute it and/or modify it under |
| the terms of the GNU General Public License as published by the Free |
| Software Foundation; either version 3, or (at your option) any later |
| version. |
| |
| GCC is distributed in the hope that it will be useful, but WITHOUT ANY |
| WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GCC; see the file COPYING3. If not see |
| <http://www.gnu.org/licenses/>. */ |
| |
| |
| #include "config.h" |
| #include "system.h" |
| #include "coretypes.h" |
| #include "target.h" |
| #include "function.h" |
| #include "rtl.h" |
| #include "tree.h" |
| #include "memmodel.h" |
| #include "tm_p.h" |
| #include "optabs.h" |
| #include "expmed.h" |
| #include "profile-count.h" |
| #include "emit-rtl.h" |
| #include "recog.h" |
| #include "diagnostic-core.h" |
| #include "stor-layout.h" |
| #include "langhooks.h" |
| #include "except.h" |
| #include "dojump.h" |
| #include "explow.h" |
| #include "expr.h" |
| #include "stringpool.h" |
| #include "common/common-target.h" |
| #include "output.h" |
| |
| static rtx break_out_memory_refs (rtx); |
| |
| |
| /* Truncate and perhaps sign-extend C as appropriate for MODE. */ |
| |
| HOST_WIDE_INT |
| trunc_int_for_mode (HOST_WIDE_INT c, machine_mode mode) |
| { |
| /* Not scalar_int_mode because we also allow pointer bound modes. */ |
| scalar_mode smode = as_a <scalar_mode> (mode); |
| int width = GET_MODE_PRECISION (smode); |
| |
| /* You want to truncate to a _what_? */ |
| gcc_assert (SCALAR_INT_MODE_P (mode)); |
| |
| /* Canonicalize BImode to 0 and STORE_FLAG_VALUE. */ |
| if (smode == BImode) |
| return c & 1 ? STORE_FLAG_VALUE : 0; |
| |
| /* Sign-extend for the requested mode. */ |
| |
| if (width < HOST_BITS_PER_WIDE_INT) |
| { |
| HOST_WIDE_INT sign = 1; |
| sign <<= width - 1; |
| c &= (sign << 1) - 1; |
| c ^= sign; |
| c -= sign; |
| } |
| |
| return c; |
| } |
| |
| /* Likewise for polynomial values, using the sign-extended representation |
| for each individual coefficient. */ |
| |
| poly_int64 |
| trunc_int_for_mode (poly_int64 x, machine_mode mode) |
| { |
| for (unsigned int i = 0; i < NUM_POLY_INT_COEFFS; ++i) |
| x.coeffs[i] = trunc_int_for_mode (x.coeffs[i], mode); |
| return x; |
| } |
| |
| /* Return an rtx for the sum of X and the integer C, given that X has |
| mode MODE. INPLACE is true if X can be modified inplace or false |
| if it must be treated as immutable. */ |
| |
| rtx |
| plus_constant (machine_mode mode, rtx x, poly_int64 c, bool inplace) |
| { |
| RTX_CODE code; |
| rtx y; |
| rtx tem; |
| int all_constant = 0; |
| |
| gcc_assert (GET_MODE (x) == VOIDmode || GET_MODE (x) == mode); |
| |
| if (known_eq (c, 0)) |
| return x; |
| |
| restart: |
| |
| code = GET_CODE (x); |
| y = x; |
| |
| switch (code) |
| { |
| CASE_CONST_SCALAR_INT: |
| return immed_wide_int_const (wi::add (rtx_mode_t (x, mode), c), mode); |
| case MEM: |
| /* If this is a reference to the constant pool, try replacing it with |
| a reference to a new constant. If the resulting address isn't |
| valid, don't return it because we have no way to validize it. */ |
| if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF |
| && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0))) |
| { |
| rtx cst = get_pool_constant (XEXP (x, 0)); |
| |
| if (GET_CODE (cst) == CONST_VECTOR |
| && GET_MODE_INNER (GET_MODE (cst)) == mode) |
| { |
| cst = gen_lowpart (mode, cst); |
| gcc_assert (cst); |
| } |
| else if (GET_MODE (cst) == VOIDmode |
| && get_pool_mode (XEXP (x, 0)) != mode) |
| break; |
| if (GET_MODE (cst) == VOIDmode || GET_MODE (cst) == mode) |
| { |
| tem = plus_constant (mode, cst, c); |
| tem = force_const_mem (GET_MODE (x), tem); |
| /* Targets may disallow some constants in the constant pool, thus |
| force_const_mem may return NULL_RTX. */ |
| if (tem && memory_address_p (GET_MODE (tem), XEXP (tem, 0))) |
| return tem; |
| } |
| } |
| break; |
| |
| case CONST: |
| /* If adding to something entirely constant, set a flag |
| so that we can add a CONST around the result. */ |
| if (inplace && shared_const_p (x)) |
| inplace = false; |
| x = XEXP (x, 0); |
| all_constant = 1; |
| goto restart; |
| |
| case SYMBOL_REF: |
| case LABEL_REF: |
| all_constant = 1; |
| break; |
| |
| case PLUS: |
| /* The interesting case is adding the integer to a sum. Look |
| for constant term in the sum and combine with C. For an |
| integer constant term or a constant term that is not an |
| explicit integer, we combine or group them together anyway. |
| |
| We may not immediately return from the recursive call here, lest |
| all_constant gets lost. */ |
| |
| if (CONSTANT_P (XEXP (x, 1))) |
| { |
| rtx term = plus_constant (mode, XEXP (x, 1), c, inplace); |
| if (term == const0_rtx) |
| x = XEXP (x, 0); |
| else if (inplace) |
| XEXP (x, 1) = term; |
| else |
| x = gen_rtx_PLUS (mode, XEXP (x, 0), term); |
| c = 0; |
| } |
| else if (rtx *const_loc = find_constant_term_loc (&y)) |
| { |
| if (!inplace) |
| { |
| /* We need to be careful since X may be shared and we can't |
| modify it in place. */ |
| x = copy_rtx (x); |
| const_loc = find_constant_term_loc (&x); |
| } |
| *const_loc = plus_constant (mode, *const_loc, c, true); |
| c = 0; |
| } |
| break; |
| |
| default: |
| if (CONST_POLY_INT_P (x)) |
| return immed_wide_int_const (const_poly_int_value (x) + c, mode); |
| break; |
| } |
| |
| if (maybe_ne (c, 0)) |
| x = gen_rtx_PLUS (mode, x, gen_int_mode (c, mode)); |
| |
| if (GET_CODE (x) == SYMBOL_REF || GET_CODE (x) == LABEL_REF) |
| return x; |
| else if (all_constant) |
| return gen_rtx_CONST (mode, x); |
| else |
| return x; |
| } |
| |
| /* If X is a sum, return a new sum like X but lacking any constant terms. |
| Add all the removed constant terms into *CONSTPTR. |
| X itself is not altered. The result != X if and only if |
| it is not isomorphic to X. */ |
| |
| rtx |
| eliminate_constant_term (rtx x, rtx *constptr) |
| { |
| rtx x0, x1; |
| rtx tem; |
| |
| if (GET_CODE (x) != PLUS) |
| return x; |
| |
| /* First handle constants appearing at this level explicitly. */ |
| if (CONST_INT_P (XEXP (x, 1)) |
| && (tem = simplify_binary_operation (PLUS, GET_MODE (x), *constptr, |
| XEXP (x, 1))) != 0 |
| && CONST_INT_P (tem)) |
| { |
| *constptr = tem; |
| return eliminate_constant_term (XEXP (x, 0), constptr); |
| } |
| |
| tem = const0_rtx; |
| x0 = eliminate_constant_term (XEXP (x, 0), &tem); |
| x1 = eliminate_constant_term (XEXP (x, 1), &tem); |
| if ((x1 != XEXP (x, 1) || x0 != XEXP (x, 0)) |
| && (tem = simplify_binary_operation (PLUS, GET_MODE (x), |
| *constptr, tem)) != 0 |
| && CONST_INT_P (tem)) |
| { |
| *constptr = tem; |
| return gen_rtx_PLUS (GET_MODE (x), x0, x1); |
| } |
| |
| return x; |
| } |
| |
| |
| /* Return a copy of X in which all memory references |
| and all constants that involve symbol refs |
| have been replaced with new temporary registers. |
| Also emit code to load the memory locations and constants |
| into those registers. |
| |
| If X contains no such constants or memory references, |
| X itself (not a copy) is returned. |
| |
| If a constant is found in the address that is not a legitimate constant |
| in an insn, it is left alone in the hope that it might be valid in the |
| address. |
| |
| X may contain no arithmetic except addition, subtraction and multiplication. |
| Values returned by expand_expr with 1 for sum_ok fit this constraint. */ |
| |
| static rtx |
| break_out_memory_refs (rtx x) |
| { |
| if (MEM_P (x) |
| || (CONSTANT_P (x) && CONSTANT_ADDRESS_P (x) |
| && GET_MODE (x) != VOIDmode)) |
| x = force_reg (GET_MODE (x), x); |
| else if (GET_CODE (x) == PLUS || GET_CODE (x) == MINUS |
| || GET_CODE (x) == MULT) |
| { |
| rtx op0 = break_out_memory_refs (XEXP (x, 0)); |
| rtx op1 = break_out_memory_refs (XEXP (x, 1)); |
| |
| if (op0 != XEXP (x, 0) || op1 != XEXP (x, 1)) |
| x = simplify_gen_binary (GET_CODE (x), GET_MODE (x), op0, op1); |
| } |
| |
| return x; |
| } |
| |
| /* 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. IN_CONST is true if this conversion is inside |
| a CONST. NO_EMIT is true if no insns should be emitted, and instead |
| it should return NULL if it can't be simplified without emitting insns. */ |
| |
| rtx |
| convert_memory_address_addr_space_1 (scalar_int_mode to_mode ATTRIBUTE_UNUSED, |
| rtx x, addr_space_t as ATTRIBUTE_UNUSED, |
| bool in_const ATTRIBUTE_UNUSED, |
| bool no_emit ATTRIBUTE_UNUSED) |
| { |
| #ifndef POINTERS_EXTEND_UNSIGNED |
| gcc_assert (GET_MODE (x) == to_mode || GET_MODE (x) == VOIDmode); |
| return x; |
| #else /* defined(POINTERS_EXTEND_UNSIGNED) */ |
| scalar_int_mode pointer_mode, address_mode, from_mode; |
| rtx temp; |
| enum rtx_code code; |
| |
| /* If X already has the right mode, just return it. */ |
| if (GET_MODE (x) == to_mode) |
| return x; |
| |
| pointer_mode = targetm.addr_space.pointer_mode (as); |
| address_mode = targetm.addr_space.address_mode (as); |
| from_mode = to_mode == pointer_mode ? address_mode : pointer_mode; |
| |
| /* Here we handle some special cases. If none of them apply, fall through |
| to the default case. */ |
| switch (GET_CODE (x)) |
| { |
| CASE_CONST_SCALAR_INT: |
| if (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (from_mode)) |
| code = TRUNCATE; |
| else if (POINTERS_EXTEND_UNSIGNED < 0) |
| break; |
| else if (POINTERS_EXTEND_UNSIGNED > 0) |
| code = ZERO_EXTEND; |
| else |
| code = SIGN_EXTEND; |
| 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.c. */ |
| 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.c |
| (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" |