/* Generate code from machine description to perform peephole optimizations.
   Copyright (C) 1987-2022 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 "bconfig.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "rtl.h"
#include "errors.h"
#include "gensupport.h"


/* While tree-walking an instruction pattern, we keep a chain
   of these `struct link's to record how to get down to the
   current position.  In each one, POS is the operand number,
   and if the operand is a vector VEC is the element number.
   VEC is -1 if the operand is not a vector.  */

struct link
{
  struct link *next;
  int pos;
  int vecelt;
};

static int max_opno;

/* Number of operands used in current peephole definition.  */

static int n_operands;

static void match_rtx (rtx, struct link *, int);
static void print_path (struct link *);
static void print_code (RTX_CODE);

static void
gen_peephole (md_rtx_info *info)
{
  rtx peep = info->def;
  int ninsns = XVECLEN (peep, 0);
  int i;

  n_operands = 0;

  printf ("  insn = ins1;\n");

  for (i = 0; i < ninsns; i++)
    {
      if (i > 0)
	{
	  printf ("  do { insn = NEXT_INSN (insn);\n");
	  printf ("       if (insn == 0) goto L%d; }\n", info->index);
	  printf ("  while (NOTE_P (insn)\n");
	  printf ("\t || (NONJUMP_INSN_P (insn)\n");
	  printf ("\t     && (GET_CODE (PATTERN (insn)) == USE\n");
	  printf ("\t\t || GET_CODE (PATTERN (insn)) == CLOBBER)));\n");

	  printf ("  if (LABEL_P (insn)\n\
      || BARRIER_P (insn))\n    goto L%d;\n", info->index);
	}

      printf ("  pat = PATTERN (insn);\n");

      /* Walk the insn's pattern, remembering at all times the path
	 down to the walking point.  */

      match_rtx (XVECEXP (peep, 0, i), NULL, info->index);
    }

  /* We get this far if the pattern matches.
     Now test the extra condition.  */

  if (XSTR (peep, 1) && XSTR (peep, 1)[0])
    printf ("  if (! (%s)) goto L%d;\n",
	    XSTR (peep, 1), info->index);

  /* If that matches, construct new pattern and put it in the first insn.
     This new pattern will never be matched.
     It exists only so that insn-extract can get the operands back.
     So use a simple regular form: a PARALLEL containing a vector
     of all the operands.  */

  printf ("  PATTERN (ins1) = gen_rtx_PARALLEL (VOIDmode, gen_rtvec_v (%d, operands));\n", n_operands);

  /* Record this define_peephole's insn code in the insn,
     as if it had been recognized to match this.  */
  printf ("  INSN_CODE (ins1) = %d;\n", info->index);

  /* Delete the remaining insns.  */
  if (ninsns > 1)
    printf ("  delete_for_peephole (NEXT_INSN (ins1), insn);\n");

  /* See reload1.cc for insertion of NOTE which guarantees that this
     cannot be zero.  */
  printf ("  return NEXT_INSN (insn);\n");

  printf (" L%d:\n\n", info->index);
}

static void
match_rtx (rtx x, struct link *path, int fail_label)
{
  RTX_CODE code;
  int i;
  int len;
  const char *fmt;
  struct link link;

  if (x == 0)
    return;


  code = GET_CODE (x);

  switch (code)
    {
    case MATCH_OPERAND:
      if (XINT (x, 0) > max_opno)
	max_opno = XINT (x, 0);
      if (XINT (x, 0) >= n_operands)
	n_operands = 1 + XINT (x, 0);

      printf ("  x = ");
      print_path (path);
      printf (";\n");

      printf ("  operands[%d] = x;\n", XINT (x, 0));
      if (XSTR (x, 1) && XSTR (x, 1)[0])
	printf ("  if (! %s (x, %smode)) goto L%d;\n",
		XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
      return;

    case MATCH_DUP:
    case MATCH_PAR_DUP:
      printf ("  x = ");
      print_path (path);
      printf (";\n");

      printf ("  if (!rtx_equal_p (operands[%d], x)) goto L%d;\n",
	      XINT (x, 0), fail_label);
      return;

    case MATCH_OP_DUP:
      printf ("  x = ");
      print_path (path);
      printf (";\n");

      printf ("  if (GET_CODE (operands[%d]) != GET_CODE (x)\n", XINT (x, 0));
      printf ("      || GET_MODE (operands[%d]) != GET_MODE (x)) goto L%d;\n",
	      XINT (x, 0), fail_label);
      printf ("  operands[%d] = x;\n", XINT (x, 0));
      link.next = path;
      link.vecelt = -1;
      for (i = 0; i < XVECLEN (x, 1); i++)
	{
	  link.pos = i;
	  match_rtx (XVECEXP (x, 1, i), &link, fail_label);
	}
      return;

    case MATCH_OPERATOR:
      if (XINT (x, 0) > max_opno)
	max_opno = XINT (x, 0);
      if (XINT (x, 0) >= n_operands)
	n_operands = 1 + XINT (x, 0);

      printf ("  x = ");
      print_path (path);
      printf (";\n");

      printf ("  operands[%d] = x;\n", XINT (x, 0));
      if (XSTR (x, 1) && XSTR (x, 1)[0])
	printf ("  if (! %s (x, %smode)) goto L%d;\n",
		XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
      link.next = path;
      link.vecelt = -1;
      for (i = 0; i < XVECLEN (x, 2); i++)
	{
	  link.pos = i;
	  match_rtx (XVECEXP (x, 2, i), &link, fail_label);
	}
      return;

    case MATCH_PARALLEL:
      if (XINT (x, 0) > max_opno)
	max_opno = XINT (x, 0);
      if (XINT (x, 0) >= n_operands)
	n_operands = 1 + XINT (x, 0);

      printf ("  x = ");
      print_path (path);
      printf (";\n");

      printf ("  if (GET_CODE (x) != PARALLEL) goto L%d;\n", fail_label);
      printf ("  operands[%d] = x;\n", XINT (x, 0));
      if (XSTR (x, 1) && XSTR (x, 1)[0])
	printf ("  if (! %s (x, %smode)) goto L%d;\n",
		XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
      link.next = path;
      link.pos = 0;
      for (i = 0; i < XVECLEN (x, 2); i++)
	{
	  link.vecelt = i;
	  match_rtx (XVECEXP (x, 2, i), &link, fail_label);
	}
      return;

    default:
      break;
    }

  printf ("  x = ");
  print_path (path);
  printf (";\n");

  printf ("  if (GET_CODE (x) != ");
  print_code (code);
  printf (") goto L%d;\n", fail_label);

  if (GET_MODE (x) != VOIDmode)
    {
      printf ("  if (GET_MODE (x) != %smode) goto L%d;\n",
	      GET_MODE_NAME (GET_MODE (x)), fail_label);
    }

  link.next = path;
  link.vecelt = -1;
  fmt = GET_RTX_FORMAT (code);
  len = GET_RTX_LENGTH (code);
  for (i = 0; i < len; i++)
    {
      link.pos = i;
      if (fmt[i] == 'e' || fmt[i] == 'u')
	match_rtx (XEXP (x, i), &link, fail_label);
      else if (fmt[i] == 'E')
	{
	  int j;
	  printf ("  if (XVECLEN (x, %d) != %d) goto L%d;\n",
		  i, XVECLEN (x, i), fail_label);
	  for (j = 0; j < XVECLEN (x, i); j++)
	    {
	      link.vecelt = j;
	      match_rtx (XVECEXP (x, i, j), &link, fail_label);
	    }
	}
      else if (fmt[i] == 'i')
	{
	  /* Make sure that at run time `x' is the RTX we want to test.  */
	  if (i != 0)
	    {
	      printf ("  x = ");
	      print_path (path);
	      printf (";\n");
	    }

	  printf ("  if (XINT (x, %d) != %d) goto L%d;\n",
		  i, XINT (x, i), fail_label);
	}
      else if (fmt[i] == 'r')
	{
	  gcc_assert (i == 0);
	  printf ("  if (REGNO (x) != %d) goto L%d;\n",
		  REGNO (x), fail_label);
	}
      else if (fmt[i] == 'w')
	{
	  /* Make sure that at run time `x' is the RTX we want to test.  */
	  if (i != 0)
	    {
	      printf ("  x = ");
	      print_path (path);
	      printf (";\n");
	    }

	  printf ("  if (XWINT (x, %d) != ", i);
	  printf (HOST_WIDE_INT_PRINT_DEC, XWINT (x, i));
	  printf (") goto L%d;\n", fail_label);
	}
      else if (fmt[i] == 's')
	{
	  /* Make sure that at run time `x' is the RTX we want to test.  */
	  if (i != 0)
	    {
	      printf ("  x = ");
	      print_path (path);
	      printf (";\n");
	    }

	  printf ("  if (strcmp (XSTR (x, %d), \"%s\")) goto L%d;\n",
		  i, XSTR (x, i), fail_label);
	}
      else if (fmt[i] == 'p')
	/* Not going to support subregs for legacy define_peeholes.  */
	gcc_unreachable ();
    }
}

/* Given a PATH, representing a path down the instruction's
   pattern from the root to a certain point, output code to
   evaluate to the rtx at that point.  */

static void
print_path (struct link *path)
{
  if (path == 0)
    printf ("pat");
  else if (path->vecelt >= 0)
    {
      printf ("XVECEXP (");
      print_path (path->next);
      printf (", %d, %d)", path->pos, path->vecelt);
    }
  else
    {
      printf ("XEXP (");
      print_path (path->next);
      printf (", %d)", path->pos);
    }
}

static void
print_code (RTX_CODE code)
{
  const char *p1;
  for (p1 = GET_RTX_NAME (code); *p1; p1++)
    putchar (TOUPPER (*p1));
}

extern int main (int, const char **);

int
main (int argc, const char **argv)
{
  max_opno = -1;

  progname = "genpeep";

  if (!init_rtx_reader_args (argc, argv))
    return (FATAL_EXIT_CODE);

  printf ("/* Generated automatically by the program `genpeep'\n\
from the machine description file `md'.  */\n\n");

  printf ("#define IN_TARGET_CODE 1\n");
  printf ("#include \"config.h\"\n");
  printf ("#include \"system.h\"\n");
  printf ("#include \"coretypes.h\"\n");
  printf ("#include \"backend.h\"\n");
  printf ("#include \"tree.h\"\n");
  printf ("#include \"rtl.h\"\n");
  printf ("#include \"insn-config.h\"\n");
  printf ("#include \"alias.h\"\n");
  printf ("#include \"varasm.h\"\n");
  printf ("#include \"stor-layout.h\"\n");
  printf ("#include \"calls.h\"\n");
  printf ("#include \"memmodel.h\"\n");
  printf ("#include \"tm_p.h\"\n");
  printf ("#include \"regs.h\"\n");
  printf ("#include \"output.h\"\n");
  printf ("#include \"recog.h\"\n");
  printf ("#include \"except.h\"\n");
  printf ("#include \"diagnostic-core.h\"\n");
  printf ("#include \"flags.h\"\n");
  printf ("#include \"tm-constrs.h\"\n\n");

  printf ("extern rtx peep_operand[];\n\n");
  printf ("#define operands peep_operand\n\n");

  printf ("rtx_insn *\npeephole (rtx_insn *ins1)\n{\n");
  printf ("  rtx_insn *insn ATTRIBUTE_UNUSED;\n");
  printf ("  rtx x ATTRIBUTE_UNUSED, pat ATTRIBUTE_UNUSED;\n\n");

  /* Early out: no peepholes for insns followed by barriers.  */
  printf ("  if (NEXT_INSN (ins1)\n");
  printf ("      && BARRIER_P (NEXT_INSN (ins1)))\n");
  printf ("    return 0;\n\n");

  /* Read the machine description.  */

  md_rtx_info info;
  while (read_md_rtx (&info))
    switch (GET_CODE (info.def))
      {
      case DEFINE_PEEPHOLE:
	gen_peephole (&info);
	break;

      default:
	break;
      }

  printf ("  return 0;\n}\n\n");

  if (max_opno == -1)
    max_opno = 1;

  printf ("rtx peep_operand[%d];\n", max_opno + 1);

  fflush (stdout);
  return (ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE);
}