866 lines
26 KiB
C
866 lines
26 KiB
C
/* Save and restore call-clobbered registers which are live across a call.
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Copyright (C) 1989, 1992, 1994, 1995, 1997, 1998,
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1999, 2000, 2001, 2002 Free Software Foundation, Inc.
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free
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Software Foundation; either version 2, or (at your option) any later
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version.
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GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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You should have received a copy of the GNU General Public License
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along with GCC; see the file COPYING. If not, write to the Free
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Software Foundation, 59 Temple Place - Suite 330, Boston, MA
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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 "function.h"
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#include "expr.h"
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#include "toplev.h"
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#include "tm_p.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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#define MOVE_MAX_WORDS (MOVE_MAX / UNITS_PER_WORD)
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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 int
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reg_save_code[FIRST_PSEUDO_REGISTER][MAX_MACHINE_MODE];
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static int
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reg_restore_code[FIRST_PSEUDO_REGISTER][MAX_MACHINE_MODE];
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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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/* Number of registers currently in hard_regs_saved. */
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static int n_regs_saved;
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/* Computed by mark_referenced_regs, all regs referenced in a given
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insn. */
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static HARD_REG_SET referenced_regs;
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/* Computed in mark_set_regs, holds all registers set by the current
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instruction. */
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static HARD_REG_SET this_insn_sets;
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static void mark_set_regs PARAMS ((rtx, rtx, void *));
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static void mark_referenced_regs PARAMS ((rtx));
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static int insert_save PARAMS ((struct insn_chain *, int, int,
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HARD_REG_SET *,
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enum machine_mode *));
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static int insert_restore PARAMS ((struct insn_chain *, int, int,
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int, enum machine_mode *));
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static struct insn_chain *insert_one_insn PARAMS ((struct insn_chain *, int,
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int, rtx));
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static void add_stored_regs PARAMS ((rtx, rtx, void *));
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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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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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enum machine_mode mode;
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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_WORDS; j++)
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{
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regno_save_mode[i][j] = HARD_REGNO_CALLER_SAVE_MODE (i, j,
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VOIDmode);
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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
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(reg_class_contents
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[(int) MODE_BASE_REG_CLASS (regno_save_mode [i][1])], 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 (mode = 0 ; mode < MAX_MACHINE_MODE; mode++)
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if (HARD_REGNO_MODE_OK (i, mode))
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{
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rtx mem = gen_rtx_MEM (mode, address);
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rtx reg = gen_rtx_REG (mode, 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][mode] = recog_memoized (saveinsn);
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reg_restore_code[i][mode] = 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][mode] != -1
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&& reg_restore_code[i][mode] != -1);
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if (ok)
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{
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extract_insn (saveinsn);
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ok = constrain_operands (1);
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extract_insn (restinsn);
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ok &= constrain_operands (1);
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}
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if (! ok)
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{
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reg_save_code[i][mode] = -1;
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reg_restore_code[i][mode] = -1;
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}
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}
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else
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{
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reg_save_code[i][mode] = -1;
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reg_restore_code[i][mode] = -1;
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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_WORDS; j++)
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if (reg_save_code [i][regno_save_mode[i][j]] == -1)
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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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end_sequence ();
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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_WORDS; 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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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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void
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setup_save_areas ()
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{
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int i, j, k;
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unsigned int r;
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HARD_REG_SET hard_regs_used;
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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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unsigned int regno = reg_renumber[i];
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unsigned int endregno
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= regno + HARD_REGNO_NREGS (regno, GET_MODE (regno_reg_rtx[i]));
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for (r = regno; r < endregno; r++)
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if (call_used_regs[r])
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SET_HARD_REG_BIT (hard_regs_used, r);
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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_WORDS; j > 0; j--)
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{
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int do_save = 1;
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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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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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if (! TEST_HARD_REG_BIT (hard_regs_used, i + k))
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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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/* We have found an acceptable mode to store in. */
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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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/* 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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regno_save_mem[i + k][1]
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= adjust_address_nv (regno_save_mem[i][j],
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regno_save_mode[i + k][1],
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k * UNITS_PER_WORD);
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}
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/* Now loop again and set the alias set of any save areas we made to
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the alias set used to represent frame objects. */
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for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
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for (j = MOVE_MAX_WORDS; j > 0; j--)
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if (regno_save_mem[i][j] != 0)
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set_mem_alias_set (regno_save_mem[i][j], get_frame_alias_set ());
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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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void
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save_call_clobbered_regs ()
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{
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struct insn_chain *chain, *next;
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enum machine_mode save_mode [FIRST_PSEUDO_REGISTER];
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CLEAR_HARD_REG_SET (hard_regs_saved);
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n_regs_saved = 0;
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for (chain = reload_insn_chain; chain != 0; chain = next)
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{
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rtx insn = chain->insn;
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enum rtx_code code = GET_CODE (insn);
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next = chain->next;
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if (chain->is_caller_save_insn)
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abort ();
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if (GET_RTX_CLASS (code) == 'i')
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{
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/* If some registers have been saved, see if INSN references
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any of them. We must restore them before the insn if so. */
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if (n_regs_saved)
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{
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int regno;
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if (code == JUMP_INSN)
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/* Restore all registers if this is a JUMP_INSN. */
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COPY_HARD_REG_SET (referenced_regs, hard_regs_saved);
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else
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{
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CLEAR_HARD_REG_SET (referenced_regs);
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mark_referenced_regs (PATTERN (insn));
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AND_HARD_REG_SET (referenced_regs, hard_regs_saved);
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}
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for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
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if (TEST_HARD_REG_BIT (referenced_regs, regno))
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regno += insert_restore (chain, 1, regno, MOVE_MAX_WORDS, save_mode);
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}
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if (code == CALL_INSN)
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{
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int regno;
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HARD_REG_SET hard_regs_to_save;
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/* Use the register life information in CHAIN to compute which
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regs are live during the call. */
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REG_SET_TO_HARD_REG_SET (hard_regs_to_save,
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&chain->live_throughout);
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/* Save hard registers always in the widest mode available. */
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for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
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if (TEST_HARD_REG_BIT (hard_regs_to_save, regno))
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save_mode [regno] = regno_save_mode [regno][1];
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else
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save_mode [regno] = VOIDmode;
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/* Look through all live pseudos, mark their hard registers
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and choose proper mode for saving. */
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EXECUTE_IF_SET_IN_REG_SET
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(&chain->live_throughout, FIRST_PSEUDO_REGISTER, regno,
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{
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int r = reg_renumber[regno];
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int nregs;
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if (r >= 0)
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{
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enum machine_mode mode;
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nregs = HARD_REGNO_NREGS (r, PSEUDO_REGNO_MODE (regno));
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mode = HARD_REGNO_CALLER_SAVE_MODE
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(r, nregs, PSEUDO_REGNO_MODE (regno));
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if (GET_MODE_BITSIZE (mode)
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> GET_MODE_BITSIZE (save_mode[r]))
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save_mode[r] = mode;
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while (nregs-- > 0)
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SET_HARD_REG_BIT (hard_regs_to_save, r + nregs);
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}
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else
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abort ();
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});
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/* Record all registers set in this call insn. These don't need
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to be saved. N.B. the call insn might set a subreg of a
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multi-hard-reg pseudo; then the pseudo is considered live
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during the call, but the subreg that is set isn't. */
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CLEAR_HARD_REG_SET (this_insn_sets);
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note_stores (PATTERN (insn), mark_set_regs, NULL);
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/* Compute which hard regs must be saved before this call. */
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AND_COMPL_HARD_REG_SET (hard_regs_to_save, call_fixed_reg_set);
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AND_COMPL_HARD_REG_SET (hard_regs_to_save, this_insn_sets);
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AND_COMPL_HARD_REG_SET (hard_regs_to_save, hard_regs_saved);
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AND_HARD_REG_SET (hard_regs_to_save, call_used_reg_set);
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for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
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if (TEST_HARD_REG_BIT (hard_regs_to_save, regno))
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regno += insert_save (chain, 1, regno, &hard_regs_to_save, save_mode);
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/* Must recompute n_regs_saved. */
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n_regs_saved = 0;
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for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
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if (TEST_HARD_REG_BIT (hard_regs_saved, regno))
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n_regs_saved++;
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}
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}
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if (chain->next == 0 || chain->next->block > chain->block)
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{
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int regno;
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/* At the end of the basic block, we must restore any registers that
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remain saved. If the last insn in the block is a JUMP_INSN, put
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the restore before the insn, otherwise, put it after the insn. */
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if (n_regs_saved)
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for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
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if (TEST_HARD_REG_BIT (hard_regs_saved, regno))
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regno += insert_restore (chain, GET_CODE (insn) == JUMP_INSN,
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regno, MOVE_MAX_WORDS, save_mode);
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}
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}
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}
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/* Here from note_stores when an insn stores a value in a register.
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Set the proper bit or bits in this_insn_sets. All pseudos that have
|
||
been assigned hard regs have had their register number changed already,
|
||
so we can ignore pseudos. */
|
||
static void
|
||
mark_set_regs (reg, setter, data)
|
||
rtx reg;
|
||
rtx setter ATTRIBUTE_UNUSED;
|
||
void *data ATTRIBUTE_UNUSED;
|
||
{
|
||
int regno, endregno, i;
|
||
enum machine_mode mode = GET_MODE (reg);
|
||
|
||
if (GET_CODE (reg) == SUBREG)
|
||
{
|
||
rtx inner = SUBREG_REG (reg);
|
||
if (GET_CODE (inner) != REG || REGNO (inner) >= FIRST_PSEUDO_REGISTER)
|
||
return;
|
||
|
||
regno = subreg_hard_regno (reg, 1);
|
||
}
|
||
else if (GET_CODE (reg) == REG
|
||
&& REGNO (reg) < FIRST_PSEUDO_REGISTER)
|
||
regno = REGNO (reg);
|
||
else
|
||
return;
|
||
|
||
endregno = regno + HARD_REGNO_NREGS (regno, mode);
|
||
|
||
for (i = regno; i < endregno; i++)
|
||
SET_HARD_REG_BIT (this_insn_sets, i);
|
||
}
|
||
|
||
/* Here from note_stores when an insn stores a value in a register.
|
||
Set the proper bit or bits in the passed regset. All pseudos that have
|
||
been assigned hard regs have had their register number changed already,
|
||
so we can ignore pseudos. */
|
||
static void
|
||
add_stored_regs (reg, setter, data)
|
||
rtx reg;
|
||
rtx setter;
|
||
void *data;
|
||
{
|
||
int regno, endregno, i;
|
||
enum machine_mode mode = GET_MODE (reg);
|
||
int offset = 0;
|
||
|
||
if (GET_CODE (setter) == CLOBBER)
|
||
return;
|
||
|
||
if (GET_CODE (reg) == SUBREG && GET_CODE (SUBREG_REG (reg)) == REG)
|
||
{
|
||
offset = subreg_regno_offset (REGNO (SUBREG_REG (reg)),
|
||
GET_MODE (SUBREG_REG (reg)),
|
||
SUBREG_BYTE (reg),
|
||
GET_MODE (reg));
|
||
reg = SUBREG_REG (reg);
|
||
}
|
||
|
||
if (GET_CODE (reg) != REG || REGNO (reg) >= FIRST_PSEUDO_REGISTER)
|
||
return;
|
||
|
||
regno = REGNO (reg) + offset;
|
||
endregno = regno + HARD_REGNO_NREGS (regno, mode);
|
||
|
||
for (i = regno; i < endregno; i++)
|
||
SET_REGNO_REG_SET ((regset) data, i);
|
||
}
|
||
|
||
/* Walk X and record all referenced registers in REFERENCED_REGS. */
|
||
static void
|
||
mark_referenced_regs (x)
|
||
rtx x;
|
||
{
|
||
enum rtx_code code = GET_CODE (x);
|
||
const char *fmt;
|
||
int i, j;
|
||
|
||
if (code == SET)
|
||
mark_referenced_regs (SET_SRC (x));
|
||
if (code == SET || code == CLOBBER)
|
||
{
|
||
x = SET_DEST (x);
|
||
code = GET_CODE (x);
|
||
if (code == REG || code == PC || code == CC0
|
||
|| (code == SUBREG && GET_CODE (SUBREG_REG (x)) == REG
|
||
/* If we're setting only part of a multi-word register,
|
||
we shall mark it as referenced, because the words
|
||
that are not being set should be restored. */
|
||
&& ((GET_MODE_SIZE (GET_MODE (x))
|
||
>= GET_MODE_SIZE (GET_MODE (SUBREG_REG (x))))
|
||
|| (GET_MODE_SIZE (GET_MODE (SUBREG_REG (x)))
|
||
<= UNITS_PER_WORD))))
|
||
return;
|
||
}
|
||
if (code == MEM || code == SUBREG)
|
||
{
|
||
x = XEXP (x, 0);
|
||
code = GET_CODE (x);
|
||
}
|
||
|
||
if (code == REG)
|
||
{
|
||
int regno = REGNO (x);
|
||
int hardregno = (regno < FIRST_PSEUDO_REGISTER ? regno
|
||
: reg_renumber[regno]);
|
||
|
||
if (hardregno >= 0)
|
||
{
|
||
int nregs = HARD_REGNO_NREGS (hardregno, GET_MODE (x));
|
||
while (nregs-- > 0)
|
||
SET_HARD_REG_BIT (referenced_regs, hardregno + nregs);
|
||
}
|
||
/* If this is a pseudo that did not get a hard register, scan its
|
||
memory location, since it might involve the use of another
|
||
register, which might be saved. */
|
||
else if (reg_equiv_mem[regno] != 0)
|
||
mark_referenced_regs (XEXP (reg_equiv_mem[regno], 0));
|
||
else if (reg_equiv_address[regno] != 0)
|
||
mark_referenced_regs (reg_equiv_address[regno]);
|
||
return;
|
||
}
|
||
|
||
fmt = GET_RTX_FORMAT (code);
|
||
for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
|
||
{
|
||
if (fmt[i] == 'e')
|
||
mark_referenced_regs (XEXP (x, i));
|
||
else if (fmt[i] == 'E')
|
||
for (j = XVECLEN (x, i) - 1; j >= 0; j--)
|
||
mark_referenced_regs (XVECEXP (x, i, j));
|
||
}
|
||
}
|
||
|
||
/* Insert a sequence of insns to restore. Place these insns in front of
|
||
CHAIN if BEFORE_P is nonzero, behind the insn otherwise. MAXRESTORE is
|
||
the maximum number of registers which should be restored during this call.
|
||
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_restore (chain, before_p, regno, maxrestore, save_mode)
|
||
struct insn_chain *chain;
|
||
int before_p;
|
||
int regno;
|
||
int maxrestore;
|
||
enum machine_mode *save_mode;
|
||
{
|
||
int i, k;
|
||
rtx pat = NULL_RTX;
|
||
int code;
|
||
unsigned int numregs = 0;
|
||
struct insn_chain *new;
|
||
rtx mem;
|
||
|
||
/* 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 ();
|
||
|
||
/* Get the pattern to emit and update our status.
|
||
|
||
See if we can restore `maxrestore' registers at once. Work
|
||
backwards to the single register case. */
|
||
for (i = maxrestore; i > 0; i--)
|
||
{
|
||
int j;
|
||
int ok = 1;
|
||
|
||
if (regno_save_mem[regno][i] == 0)
|
||
continue;
|
||
|
||
for (j = 0; j < i; j++)
|
||
if (! TEST_HARD_REG_BIT (hard_regs_saved, regno + j))
|
||
{
|
||
ok = 0;
|
||
break;
|
||
}
|
||
/* Must do this one restore at a time */
|
||
if (! ok)
|
||
continue;
|
||
|
||
numregs = i;
|
||
break;
|
||
}
|
||
|
||
mem = regno_save_mem [regno][numregs];
|
||
if (save_mode [regno] != VOIDmode
|
||
&& save_mode [regno] != GET_MODE (mem)
|
||
&& numregs == (unsigned int) HARD_REGNO_NREGS (regno, save_mode [regno]))
|
||
mem = adjust_address (mem, save_mode[regno], 0);
|
||
pat = gen_rtx_SET (VOIDmode,
|
||
gen_rtx_REG (GET_MODE (mem),
|
||
regno), mem);
|
||
code = reg_restore_code[regno][GET_MODE (mem)];
|
||
new = insert_one_insn (chain, before_p, code, pat);
|
||
|
||
/* Clear status for all registers we restored. */
|
||
for (k = 0; k < i; k++)
|
||
{
|
||
CLEAR_HARD_REG_BIT (hard_regs_saved, regno + k);
|
||
SET_REGNO_REG_SET (&new->dead_or_set, regno + k);
|
||
n_regs_saved--;
|
||
}
|
||
|
||
/* Tell our callers how many extra registers we saved/restored */
|
||
return numregs - 1;
|
||
}
|
||
|
||
/* Like insert_restore above, but save registers instead. */
|
||
|
||
static int
|
||
insert_save (chain, before_p, regno, to_save, save_mode)
|
||
struct insn_chain *chain;
|
||
int before_p;
|
||
int regno;
|
||
HARD_REG_SET *to_save;
|
||
enum machine_mode *save_mode;
|
||
{
|
||
int i;
|
||
unsigned int k;
|
||
rtx pat = NULL_RTX;
|
||
int code;
|
||
unsigned int numregs = 0;
|
||
struct insn_chain *new;
|
||
rtx mem;
|
||
|
||
/* 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 ();
|
||
|
||
/* Get the pattern to emit and update our status.
|
||
|
||
See if we can save several registers with a single instruction.
|
||
Work backwards to the single register case. */
|
||
for (i = MOVE_MAX_WORDS; i > 0; i--)
|
||
{
|
||
int j;
|
||
int ok = 1;
|
||
if (regno_save_mem[regno][i] == 0)
|
||
continue;
|
||
|
||
for (j = 0; j < i; j++)
|
||
if (! TEST_HARD_REG_BIT (*to_save, regno + j))
|
||
{
|
||
ok = 0;
|
||
break;
|
||
}
|
||
/* Must do this one save at a time */
|
||
if (! ok)
|
||
continue;
|
||
|
||
numregs = i;
|
||
break;
|
||
}
|
||
|
||
mem = regno_save_mem [regno][numregs];
|
||
if (save_mode [regno] != VOIDmode
|
||
&& save_mode [regno] != GET_MODE (mem)
|
||
&& numregs == (unsigned int) HARD_REGNO_NREGS (regno, save_mode [regno]))
|
||
mem = adjust_address (mem, save_mode[regno], 0);
|
||
pat = gen_rtx_SET (VOIDmode, mem,
|
||
gen_rtx_REG (GET_MODE (mem),
|
||
regno));
|
||
code = reg_save_code[regno][GET_MODE (mem)];
|
||
new = insert_one_insn (chain, before_p, code, pat);
|
||
|
||
/* Set hard_regs_saved and dead_or_set for all the registers we saved. */
|
||
for (k = 0; k < numregs; k++)
|
||
{
|
||
SET_HARD_REG_BIT (hard_regs_saved, regno + k);
|
||
SET_REGNO_REG_SET (&new->dead_or_set, regno + k);
|
||
n_regs_saved++;
|
||
}
|
||
|
||
/* Tell our callers how many extra registers we saved/restored */
|
||
return numregs - 1;
|
||
}
|
||
|
||
/* Emit a new caller-save insn and set the code. */
|
||
static struct insn_chain *
|
||
insert_one_insn (chain, before_p, code, pat)
|
||
struct insn_chain *chain;
|
||
int before_p;
|
||
int code;
|
||
rtx pat;
|
||
{
|
||
rtx insn = chain->insn;
|
||
struct insn_chain *new;
|
||
|
||
#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)
|
||
&& before_p
|
||
&& reg_referenced_p (cc0_rtx, PATTERN (insn)))
|
||
chain = chain->prev, insn = chain->insn;
|
||
#endif
|
||
|
||
new = new_insn_chain ();
|
||
if (before_p)
|
||
{
|
||
rtx link;
|
||
|
||
new->prev = chain->prev;
|
||
if (new->prev != 0)
|
||
new->prev->next = new;
|
||
else
|
||
reload_insn_chain = new;
|
||
|
||
chain->prev = new;
|
||
new->next = chain;
|
||
new->insn = emit_insn_before (pat, insn);
|
||
/* ??? It would be nice if we could exclude the already / still saved
|
||
registers from the live sets. */
|
||
COPY_REG_SET (&new->live_throughout, &chain->live_throughout);
|
||
/* Registers that die in CHAIN->INSN still live in the new insn. */
|
||
for (link = REG_NOTES (chain->insn); link; link = XEXP (link, 1))
|
||
{
|
||
if (REG_NOTE_KIND (link) == REG_DEAD)
|
||
{
|
||
rtx reg = XEXP (link, 0);
|
||
int regno, i;
|
||
|
||
if (GET_CODE (reg) != REG)
|
||
abort ();
|
||
|
||
regno = REGNO (reg);
|
||
if (regno >= FIRST_PSEUDO_REGISTER)
|
||
regno = reg_renumber[regno];
|
||
if (regno < 0)
|
||
continue;
|
||
for (i = HARD_REGNO_NREGS (regno, GET_MODE (reg)) - 1;
|
||
i >= 0; i--)
|
||
SET_REGNO_REG_SET (&new->live_throughout, regno + i);
|
||
}
|
||
}
|
||
CLEAR_REG_SET (&new->dead_or_set);
|
||
if (chain->insn == BLOCK_HEAD (chain->block))
|
||
BLOCK_HEAD (chain->block) = new->insn;
|
||
}
|
||
else
|
||
{
|
||
new->next = chain->next;
|
||
if (new->next != 0)
|
||
new->next->prev = new;
|
||
chain->next = new;
|
||
new->prev = chain;
|
||
new->insn = emit_insn_after (pat, insn);
|
||
/* ??? It would be nice if we could exclude the already / still saved
|
||
registers from the live sets, and observe REG_UNUSED notes. */
|
||
COPY_REG_SET (&new->live_throughout, &chain->live_throughout);
|
||
/* Registers that are set in CHAIN->INSN live in the new insn.
|
||
(Unless there is a REG_UNUSED note for them, but we don't
|
||
look for them here.) */
|
||
note_stores (PATTERN (chain->insn), add_stored_regs,
|
||
&new->live_throughout);
|
||
CLEAR_REG_SET (&new->dead_or_set);
|
||
if (chain->insn == BLOCK_END (chain->block))
|
||
BLOCK_END (chain->block) = new->insn;
|
||
}
|
||
new->block = chain->block;
|
||
new->is_caller_save_insn = 1;
|
||
|
||
INSN_CODE (new->insn) = code;
|
||
return new;
|
||
}
|