764 lines
24 KiB
C
764 lines
24 KiB
C
/* Save and restore call-clobbered registers which are live across a call.
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Copyright (C) 1989, 1992, 94-95, 1997, 1998 Free Software Foundation, Inc.
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This file is part of GNU CC.
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GNU CC is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU CC is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License 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 GNU CC; see the file COPYING. If not, write to
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the Free Software Foundation, 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include "config.h"
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#include "system.h"
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#include "rtl.h"
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#include "insn-config.h"
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#include "flags.h"
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#include "regs.h"
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#include "hard-reg-set.h"
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#include "recog.h"
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#include "basic-block.h"
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#include "reload.h"
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#include "expr.h"
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#include "toplev.h"
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#ifndef MAX_MOVE_MAX
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#define MAX_MOVE_MAX MOVE_MAX
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#endif
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#ifndef MIN_UNITS_PER_WORD
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#define MIN_UNITS_PER_WORD UNITS_PER_WORD
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#endif
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/* Modes for each hard register that we can save. The smallest mode is wide
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enough to save the entire contents of the register. When saving the
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register because it is live we first try to save in multi-register modes.
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If that is not possible the save is done one register at a time. */
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static enum machine_mode
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regno_save_mode[FIRST_PSEUDO_REGISTER][MAX_MOVE_MAX / MIN_UNITS_PER_WORD + 1];
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/* For each hard register, a place on the stack where it can be saved,
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if needed. */
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static rtx
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regno_save_mem[FIRST_PSEUDO_REGISTER][MAX_MOVE_MAX / MIN_UNITS_PER_WORD + 1];
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/* We will only make a register eligible for caller-save if it can be
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saved in its widest mode with a simple SET insn as long as the memory
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address is valid. We record the INSN_CODE is those insns here since
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when we emit them, the addresses might not be valid, so they might not
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be recognized. */
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static enum insn_code
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reg_save_code[FIRST_PSEUDO_REGISTER][MAX_MOVE_MAX / MIN_UNITS_PER_WORD + 1];
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static enum insn_code
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reg_restore_code[FIRST_PSEUDO_REGISTER][MAX_MOVE_MAX / MIN_UNITS_PER_WORD + 1];
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/* Set of hard regs currently live (during scan of all insns). */
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static HARD_REG_SET hard_regs_live;
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/* Set of hard regs currently residing in save area (during insn scan). */
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static HARD_REG_SET hard_regs_saved;
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/* Set of hard regs which need to be restored before referenced. */
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static HARD_REG_SET hard_regs_need_restore;
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/* Number of registers currently in hard_regs_saved. */
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int n_regs_saved;
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static void set_reg_live PROTO((rtx, rtx));
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static void clear_reg_live PROTO((rtx));
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static void restore_referenced_regs PROTO((rtx, rtx, enum machine_mode));
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static int insert_save_restore PROTO((rtx, int, int,
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enum machine_mode, int));
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/* Initialize for caller-save.
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Look at all the hard registers that are used by a call and for which
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regclass.c has not already excluded from being used across a call.
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Ensure that we can find a mode to save the register and that there is a
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simple insn to save and restore the register. This latter check avoids
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problems that would occur if we tried to save the MQ register of some
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machines directly into memory. */
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void
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init_caller_save ()
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{
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char *first_obj = (char *) oballoc (0);
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rtx addr_reg;
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int offset;
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rtx address;
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int i, j;
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/* First find all the registers that we need to deal with and all
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the modes that they can have. If we can't find a mode to use,
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we can't have the register live over calls. */
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for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
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{
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if (call_used_regs[i] && ! call_fixed_regs[i])
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{
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for (j = 1; j <= MOVE_MAX / UNITS_PER_WORD; j++)
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{
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regno_save_mode[i][j] = choose_hard_reg_mode (i, j);
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if (regno_save_mode[i][j] == VOIDmode && j == 1)
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{
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call_fixed_regs[i] = 1;
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SET_HARD_REG_BIT (call_fixed_reg_set, i);
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}
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}
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}
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else
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regno_save_mode[i][1] = VOIDmode;
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}
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/* The following code tries to approximate the conditions under which
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we can easily save and restore a register without scratch registers or
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other complexities. It will usually work, except under conditions where
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the validity of an insn operand is dependent on the address offset.
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No such cases are currently known.
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We first find a typical offset from some BASE_REG_CLASS register.
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This address is chosen by finding the first register in the class
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and by finding the smallest power of two that is a valid offset from
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that register in every mode we will use to save registers. */
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for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
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if (TEST_HARD_REG_BIT (reg_class_contents[(int) BASE_REG_CLASS], i))
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break;
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if (i == FIRST_PSEUDO_REGISTER)
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abort ();
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addr_reg = gen_rtx_REG (Pmode, i);
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for (offset = 1 << (HOST_BITS_PER_INT / 2); offset; offset >>= 1)
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{
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address = gen_rtx_PLUS (Pmode, addr_reg, GEN_INT (offset));
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for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
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if (regno_save_mode[i][1] != VOIDmode
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&& ! strict_memory_address_p (regno_save_mode[i][1], address))
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break;
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if (i == FIRST_PSEUDO_REGISTER)
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break;
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}
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/* If we didn't find a valid address, we must use register indirect. */
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if (offset == 0)
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address = addr_reg;
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/* Next we try to form an insn to save and restore the register. We
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see if such an insn is recognized and meets its constraints. */
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start_sequence ();
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for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
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for (j = 1; j <= MOVE_MAX / UNITS_PER_WORD; j++)
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if (regno_save_mode[i][j] != VOIDmode)
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{
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rtx mem = gen_rtx_MEM (regno_save_mode[i][j], address);
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rtx reg = gen_rtx_REG (regno_save_mode[i][j], i);
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rtx savepat = gen_rtx_SET (VOIDmode, mem, reg);
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rtx restpat = gen_rtx_SET (VOIDmode, reg, mem);
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rtx saveinsn = emit_insn (savepat);
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rtx restinsn = emit_insn (restpat);
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int ok;
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reg_save_code[i][j] = recog_memoized (saveinsn);
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reg_restore_code[i][j] = recog_memoized (restinsn);
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/* Now extract both insns and see if we can meet their
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constraints. */
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ok = (reg_save_code[i][j] != -1 && reg_restore_code[i][j] != -1);
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if (ok)
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{
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insn_extract (saveinsn);
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ok = constrain_operands (reg_save_code[i][j], 1);
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insn_extract (restinsn);
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ok &= constrain_operands (reg_restore_code[i][j], 1);
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}
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if (! ok)
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{
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regno_save_mode[i][j] = VOIDmode;
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if (j == 1)
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{
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call_fixed_regs[i] = 1;
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SET_HARD_REG_BIT (call_fixed_reg_set, i);
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}
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}
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}
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end_sequence ();
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obfree (first_obj);
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}
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/* Initialize save areas by showing that we haven't allocated any yet. */
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void
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init_save_areas ()
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{
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int i, j;
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for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
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for (j = 1; j <= MOVE_MAX / UNITS_PER_WORD; j++)
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regno_save_mem[i][j] = 0;
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}
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/* Allocate save areas for any hard registers that might need saving.
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We take a conservative approach here and look for call-clobbered hard
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registers that are assigned to pseudos that cross calls. This may
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overestimate slightly (especially if some of these registers are later
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used as spill registers), but it should not be significant.
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Then perform register elimination in the addresses of the save area
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locations; return 1 if all eliminated addresses are strictly valid.
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We assume that our caller has set up the elimination table to the
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worst (largest) possible offsets.
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Set *PCHANGED to 1 if we had to allocate some memory for the save area.
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Future work:
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In the fallback case we should iterate backwards across all possible
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modes for the save, choosing the largest available one instead of
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falling back to the smallest mode immediately. (eg TF -> DF -> SF).
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We do not try to use "move multiple" instructions that exist
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on some machines (such as the 68k moveml). It could be a win to try
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and use them when possible. The hard part is doing it in a way that is
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machine independent since they might be saving non-consecutive
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registers. (imagine caller-saving d0,d1,a0,a1 on the 68k) */
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int
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setup_save_areas (pchanged)
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int *pchanged;
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{
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int i, j, k;
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HARD_REG_SET hard_regs_used;
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int ok = 1;
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/* Allocate space in the save area for the largest multi-register
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pseudos first, then work backwards to single register
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pseudos. */
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/* Find and record all call-used hard-registers in this function. */
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CLEAR_HARD_REG_SET (hard_regs_used);
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for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
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if (reg_renumber[i] >= 0 && REG_N_CALLS_CROSSED (i) > 0)
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{
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int regno = reg_renumber[i];
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int endregno
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= regno + HARD_REGNO_NREGS (regno, GET_MODE (regno_reg_rtx[i]));
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int nregs = endregno - regno;
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for (j = 0; j < nregs; j++)
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{
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if (call_used_regs[regno+j])
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SET_HARD_REG_BIT (hard_regs_used, regno+j);
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}
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}
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/* Now run through all the call-used hard-registers and allocate
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space for them in the caller-save area. Try to allocate space
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in a manner which allows multi-register saves/restores to be done. */
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for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
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for (j = MOVE_MAX / UNITS_PER_WORD; j > 0; j--)
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{
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int ok = 1;
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int do_save;
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/* If no mode exists for this size, try another. Also break out
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if we have already saved this hard register. */
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if (regno_save_mode[i][j] == VOIDmode || regno_save_mem[i][1] != 0)
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continue;
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/* See if any register in this group has been saved. */
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do_save = 1;
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for (k = 0; k < j; k++)
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if (regno_save_mem[i + k][1])
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{
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do_save = 0;
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break;
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}
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if (! do_save)
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continue;
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for (k = 0; k < j; k++)
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{
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int regno = i + k;
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ok &= (TEST_HARD_REG_BIT (hard_regs_used, regno) != 0);
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}
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/* We have found an acceptable mode to store in. */
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if (ok)
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{
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regno_save_mem[i][j]
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= assign_stack_local (regno_save_mode[i][j],
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GET_MODE_SIZE (regno_save_mode[i][j]), 0);
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/* Setup single word save area just in case... */
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for (k = 0; k < j; k++)
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{
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/* This should not depend on WORDS_BIG_ENDIAN.
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The order of words in regs is the same as in memory. */
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rtx temp = gen_rtx_MEM (regno_save_mode[i+k][1],
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XEXP (regno_save_mem[i][j], 0));
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regno_save_mem[i+k][1]
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= adj_offsettable_operand (temp, k * UNITS_PER_WORD);
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}
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*pchanged = 1;
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}
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}
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for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
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for (j = 1; j <= MOVE_MAX / UNITS_PER_WORD; j++)
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if (regno_save_mem[i][j] != 0)
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ok &= strict_memory_address_p (GET_MODE (regno_save_mem[i][j]),
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XEXP (eliminate_regs (regno_save_mem[i][j], 0, NULL_RTX), 0));
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return ok;
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}
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/* Find the places where hard regs are live across calls and save them.
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INSN_MODE is the mode to assign to any insns that we add. This is used
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by reload to determine whether or not reloads or register eliminations
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need be done on these insns. */
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void
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save_call_clobbered_regs (insn_mode)
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enum machine_mode insn_mode;
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{
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rtx insn;
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int b;
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for (b = 0; b < n_basic_blocks; b++)
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{
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regset regs_live = basic_block_live_at_start[b];
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rtx prev_block_last = PREV_INSN (basic_block_head[b]);
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int i, j;
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int regno;
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/* Compute hard regs live at start of block -- this is the
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real hard regs marked live, plus live pseudo regs that
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have been renumbered to hard regs. No registers have yet been
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saved because we restore all of them before the end of the basic
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block. */
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REG_SET_TO_HARD_REG_SET (hard_regs_live, regs_live);
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CLEAR_HARD_REG_SET (hard_regs_saved);
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CLEAR_HARD_REG_SET (hard_regs_need_restore);
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n_regs_saved = 0;
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EXECUTE_IF_SET_IN_REG_SET (regs_live, 0, i,
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{
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if ((regno = reg_renumber[i]) >= 0)
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for (j = regno;
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j < regno + HARD_REGNO_NREGS (regno,
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PSEUDO_REGNO_MODE (i));
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j++)
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SET_HARD_REG_BIT (hard_regs_live, j);
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});
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/* Now scan the insns in the block, keeping track of what hard
|
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regs are live as we go. When we see a call, save the live
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call-clobbered hard regs. */
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||
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for (insn = basic_block_head[b]; ; insn = NEXT_INSN (insn))
|
||
{
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||
RTX_CODE code = GET_CODE (insn);
|
||
|
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if (GET_RTX_CLASS (code) == 'i')
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{
|
||
rtx link;
|
||
|
||
/* If some registers have been saved, see if INSN references
|
||
any of them. We must restore them before the insn if so. */
|
||
|
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if (n_regs_saved)
|
||
restore_referenced_regs (PATTERN (insn), insn, insn_mode);
|
||
|
||
/* NB: the normal procedure is to first enliven any
|
||
registers set by insn, then deaden any registers that
|
||
had their last use at insn. This is incorrect now,
|
||
since multiple pseudos may have been mapped to the
|
||
same hard reg, and the death notes are ambiguous. So
|
||
it must be done in the other, safe, order. */
|
||
|
||
for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
|
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if (REG_NOTE_KIND (link) == REG_DEAD)
|
||
clear_reg_live (XEXP (link, 0));
|
||
|
||
/* When we reach a call, we need to save all registers that are
|
||
live, call-used, not fixed, and not already saved. We must
|
||
test at this point because registers that die in a CALL_INSN
|
||
are not live across the call and likewise for registers that
|
||
are born in the CALL_INSN.
|
||
|
||
If registers are filled with parameters for this function,
|
||
and some of these are also being set by this function, then
|
||
they will not appear to die (no REG_DEAD note for them),
|
||
to check if in fact they do, collect the set registers in
|
||
hard_regs_live first. */
|
||
|
||
if (code == CALL_INSN)
|
||
{
|
||
HARD_REG_SET this_call_sets;
|
||
{
|
||
HARD_REG_SET old_hard_regs_live;
|
||
|
||
/* Save the hard_regs_live information. */
|
||
COPY_HARD_REG_SET (old_hard_regs_live, hard_regs_live);
|
||
|
||
/* Now calculate hard_regs_live for this CALL_INSN
|
||
only. */
|
||
CLEAR_HARD_REG_SET (hard_regs_live);
|
||
note_stores (PATTERN (insn), set_reg_live);
|
||
COPY_HARD_REG_SET (this_call_sets, hard_regs_live);
|
||
|
||
/* Restore the hard_regs_live information. */
|
||
COPY_HARD_REG_SET (hard_regs_live, old_hard_regs_live);
|
||
}
|
||
|
||
for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
|
||
if (call_used_regs[regno] && ! call_fixed_regs[regno]
|
||
&& TEST_HARD_REG_BIT (hard_regs_live, regno)
|
||
/* It must not be set by this instruction. */
|
||
&& ! TEST_HARD_REG_BIT (this_call_sets, regno)
|
||
&& ! TEST_HARD_REG_BIT (hard_regs_saved, regno))
|
||
regno += insert_save_restore (insn, 1, regno,
|
||
insn_mode, 0);
|
||
|
||
/* Put the information for this CALL_INSN on top of what
|
||
we already had. */
|
||
IOR_HARD_REG_SET (hard_regs_live, this_call_sets);
|
||
COPY_HARD_REG_SET (hard_regs_need_restore, hard_regs_saved);
|
||
|
||
/* Must recompute n_regs_saved. */
|
||
n_regs_saved = 0;
|
||
for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
|
||
if (TEST_HARD_REG_BIT (hard_regs_saved, regno))
|
||
n_regs_saved++;
|
||
}
|
||
else
|
||
{
|
||
note_stores (PATTERN (insn), set_reg_live);
|
||
#ifdef AUTO_INC_DEC
|
||
for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
|
||
if (REG_NOTE_KIND (link) == REG_INC)
|
||
set_reg_live (XEXP (link, 0), NULL_RTX);
|
||
#endif
|
||
}
|
||
|
||
for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
|
||
if (REG_NOTE_KIND (link) == REG_UNUSED)
|
||
clear_reg_live (XEXP (link, 0));
|
||
}
|
||
|
||
if (insn == basic_block_end[b])
|
||
break;
|
||
}
|
||
|
||
/* At the end of the basic block, we must restore any registers that
|
||
remain saved. If the last insn in the block is a JUMP_INSN, put
|
||
the restore before the insn, otherwise, put it after the insn. */
|
||
|
||
if (n_regs_saved)
|
||
for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
|
||
if (TEST_HARD_REG_BIT (hard_regs_need_restore, regno))
|
||
regno += insert_save_restore ((GET_CODE (insn) == JUMP_INSN
|
||
? insn : NEXT_INSN (insn)), 0,
|
||
regno, insn_mode, MOVE_MAX / UNITS_PER_WORD);
|
||
|
||
/* If we added any insns at the start of the block, update the start
|
||
of the block to point at those insns. */
|
||
basic_block_head[b] = NEXT_INSN (prev_block_last);
|
||
}
|
||
}
|
||
|
||
/* Here from note_stores when an insn stores a value in a register.
|
||
Set the proper bit or bits in hard_regs_live. All pseudos that have
|
||
been assigned hard regs have had their register number changed already,
|
||
so we can ignore pseudos. */
|
||
|
||
static void
|
||
set_reg_live (reg, setter)
|
||
rtx reg;
|
||
rtx setter ATTRIBUTE_UNUSED;
|
||
{
|
||
register int regno, endregno, i;
|
||
enum machine_mode mode = GET_MODE (reg);
|
||
int word = 0;
|
||
|
||
if (GET_CODE (reg) == SUBREG)
|
||
{
|
||
word = SUBREG_WORD (reg);
|
||
reg = SUBREG_REG (reg);
|
||
}
|
||
|
||
if (GET_CODE (reg) != REG || REGNO (reg) >= FIRST_PSEUDO_REGISTER)
|
||
return;
|
||
|
||
regno = REGNO (reg) + word;
|
||
endregno = regno + HARD_REGNO_NREGS (regno, mode);
|
||
|
||
for (i = regno; i < endregno; i++)
|
||
{
|
||
SET_HARD_REG_BIT (hard_regs_live, i);
|
||
CLEAR_HARD_REG_BIT (hard_regs_saved, i);
|
||
CLEAR_HARD_REG_BIT (hard_regs_need_restore, i);
|
||
}
|
||
}
|
||
|
||
/* Here when a REG_DEAD note records the last use of a reg. Clear
|
||
the appropriate bit or bits in hard_regs_live. Again we can ignore
|
||
pseudos. */
|
||
|
||
static void
|
||
clear_reg_live (reg)
|
||
rtx reg;
|
||
{
|
||
register int regno, endregno, i;
|
||
|
||
if (GET_CODE (reg) != REG || REGNO (reg) >= FIRST_PSEUDO_REGISTER)
|
||
return;
|
||
|
||
regno = REGNO (reg);
|
||
endregno= regno + HARD_REGNO_NREGS (regno, GET_MODE (reg));
|
||
|
||
for (i = regno; i < endregno; i++)
|
||
{
|
||
CLEAR_HARD_REG_BIT (hard_regs_live, i);
|
||
CLEAR_HARD_REG_BIT (hard_regs_need_restore, i);
|
||
CLEAR_HARD_REG_BIT (hard_regs_saved, i);
|
||
}
|
||
}
|
||
|
||
/* If any register currently residing in the save area is referenced in X,
|
||
which is part of INSN, emit code to restore the register in front of INSN.
|
||
INSN_MODE is the mode to assign to any insns that we add. */
|
||
|
||
static void
|
||
restore_referenced_regs (x, insn, insn_mode)
|
||
rtx x;
|
||
rtx insn;
|
||
enum machine_mode insn_mode;
|
||
{
|
||
enum rtx_code code = GET_CODE (x);
|
||
char *fmt;
|
||
int i, j;
|
||
|
||
if (code == CLOBBER)
|
||
return;
|
||
|
||
if (code == REG)
|
||
{
|
||
int regno = REGNO (x);
|
||
|
||
/* If this is a pseudo, scan its memory location, since it might
|
||
involve the use of another register, which might be saved. */
|
||
|
||
if (regno >= FIRST_PSEUDO_REGISTER
|
||
&& reg_equiv_mem[regno] != 0)
|
||
restore_referenced_regs (XEXP (reg_equiv_mem[regno], 0),
|
||
insn, insn_mode);
|
||
else if (regno >= FIRST_PSEUDO_REGISTER
|
||
&& reg_equiv_address[regno] != 0)
|
||
restore_referenced_regs (reg_equiv_address[regno],
|
||
insn, insn_mode);
|
||
|
||
/* Otherwise if this is a hard register, restore any piece of it that
|
||
is currently saved. */
|
||
|
||
else if (regno < FIRST_PSEUDO_REGISTER)
|
||
{
|
||
int numregs = HARD_REGNO_NREGS (regno, GET_MODE (x));
|
||
/* Save at most SAVEREGS at a time. This can not be larger than
|
||
MOVE_MAX, because that causes insert_save_restore to fail. */
|
||
int saveregs = MIN (numregs, MOVE_MAX / UNITS_PER_WORD);
|
||
int endregno = regno + numregs;
|
||
|
||
for (i = regno; i < endregno; i++)
|
||
if (TEST_HARD_REG_BIT (hard_regs_need_restore, i))
|
||
i += insert_save_restore (insn, 0, i, insn_mode, saveregs);
|
||
}
|
||
|
||
return;
|
||
}
|
||
|
||
fmt = GET_RTX_FORMAT (code);
|
||
for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
|
||
{
|
||
if (fmt[i] == 'e')
|
||
restore_referenced_regs (XEXP (x, i), insn, insn_mode);
|
||
else if (fmt[i] == 'E')
|
||
for (j = XVECLEN (x, i) - 1; j >= 0; j--)
|
||
restore_referenced_regs (XVECEXP (x, i, j), insn, insn_mode);
|
||
}
|
||
}
|
||
|
||
/* Insert a sequence of insns to save or restore, SAVE_P says which,
|
||
REGNO. Place these insns in front of INSN. INSN_MODE is the mode
|
||
to assign to these insns. MAXRESTORE is the maximum number of registers
|
||
which should be restored during this call (when SAVE_P == 0). It should
|
||
never be less than 1 since we only work with entire registers.
|
||
|
||
Note that we have verified in init_caller_save that we can do this
|
||
with a simple SET, so use it. Set INSN_CODE to what we save there
|
||
since the address might not be valid so the insn might not be recognized.
|
||
These insns will be reloaded and have register elimination done by
|
||
find_reload, so we need not worry about that here.
|
||
|
||
Return the extra number of registers saved. */
|
||
|
||
static int
|
||
insert_save_restore (insn, save_p, regno, insn_mode, maxrestore)
|
||
rtx insn;
|
||
int save_p;
|
||
int regno;
|
||
enum machine_mode insn_mode;
|
||
int maxrestore;
|
||
{
|
||
rtx pat = NULL_RTX;
|
||
enum insn_code code = CODE_FOR_nothing;
|
||
int numregs = 0;
|
||
|
||
/* A common failure mode if register status is not correct in the RTL
|
||
is for this routine to be called with a REGNO we didn't expect to
|
||
save. That will cause us to write an insn with a (nil) SET_DEST
|
||
or SET_SRC. Instead of doing so and causing a crash later, check
|
||
for this common case and abort here instead. This will remove one
|
||
step in debugging such problems. */
|
||
|
||
if (regno_save_mem[regno][1] == 0)
|
||
abort ();
|
||
|
||
#ifdef HAVE_cc0
|
||
/* If INSN references CC0, put our insns in front of the insn that sets
|
||
CC0. This is always safe, since the only way we could be passed an
|
||
insn that references CC0 is for a restore, and doing a restore earlier
|
||
isn't a problem. We do, however, assume here that CALL_INSNs don't
|
||
reference CC0. Guard against non-INSN's like CODE_LABEL. */
|
||
|
||
if ((GET_CODE (insn) == INSN || GET_CODE (insn) == JUMP_INSN)
|
||
&& reg_referenced_p (cc0_rtx, PATTERN (insn)))
|
||
insn = prev_nonnote_insn (insn);
|
||
#endif
|
||
|
||
/* Get the pattern to emit and update our status. */
|
||
if (save_p)
|
||
{
|
||
int i, j, k;
|
||
int ok;
|
||
|
||
/* See if we can save several registers with a single instruction.
|
||
Work backwards to the single register case. */
|
||
for (i = MOVE_MAX / UNITS_PER_WORD; i > 0; i--)
|
||
{
|
||
ok = 1;
|
||
if (regno_save_mem[regno][i] != 0)
|
||
for (j = 0; j < i; j++)
|
||
{
|
||
if (! call_used_regs[regno + j] || call_fixed_regs[regno + j]
|
||
|| ! TEST_HARD_REG_BIT (hard_regs_live, regno + j)
|
||
|| TEST_HARD_REG_BIT (hard_regs_saved, regno + j))
|
||
ok = 0;
|
||
}
|
||
else
|
||
continue;
|
||
|
||
/* Must do this one save at a time */
|
||
if (! ok)
|
||
continue;
|
||
|
||
pat = gen_rtx_SET (VOIDmode, regno_save_mem[regno][i],
|
||
gen_rtx_REG (GET_MODE (regno_save_mem[regno][i]),
|
||
regno));
|
||
code = reg_save_code[regno][i];
|
||
|
||
/* Set hard_regs_saved for all the registers we saved. */
|
||
for (k = 0; k < i; k++)
|
||
{
|
||
SET_HARD_REG_BIT (hard_regs_saved, regno + k);
|
||
SET_HARD_REG_BIT (hard_regs_need_restore, regno + k);
|
||
n_regs_saved++;
|
||
}
|
||
|
||
numregs = i;
|
||
break;
|
||
}
|
||
}
|
||
else
|
||
{
|
||
int i, j, k;
|
||
int ok;
|
||
|
||
/* See if we can restore `maxrestore' registers at once. Work
|
||
backwards to the single register case. */
|
||
for (i = maxrestore; i > 0; i--)
|
||
{
|
||
ok = 1;
|
||
if (regno_save_mem[regno][i])
|
||
for (j = 0; j < i; j++)
|
||
{
|
||
if (! TEST_HARD_REG_BIT (hard_regs_need_restore, regno + j))
|
||
ok = 0;
|
||
}
|
||
else
|
||
continue;
|
||
|
||
/* Must do this one restore at a time */
|
||
if (! ok)
|
||
continue;
|
||
|
||
pat = gen_rtx_SET (VOIDmode,
|
||
gen_rtx_REG (GET_MODE (regno_save_mem[regno][i]),
|
||
regno),
|
||
regno_save_mem[regno][i]);
|
||
code = reg_restore_code[regno][i];
|
||
|
||
|
||
/* Clear status for all registers we restored. */
|
||
for (k = 0; k < i; k++)
|
||
{
|
||
CLEAR_HARD_REG_BIT (hard_regs_need_restore, regno + k);
|
||
n_regs_saved--;
|
||
}
|
||
|
||
numregs = i;
|
||
break;
|
||
}
|
||
}
|
||
/* Emit the insn and set the code and mode. */
|
||
|
||
insn = emit_insn_before (pat, insn);
|
||
PUT_MODE (insn, insn_mode);
|
||
INSN_CODE (insn) = code;
|
||
|
||
/* Tell our callers how many extra registers we saved/restored */
|
||
return numregs - 1;
|
||
}
|