source: trunk/third/gcc/genoutput.c @ 8834

/* Generate code from to output assembler insns as recognized from rtl.
   Copyright (C) 1987, 1988, 1992, 1994, 1995 Free Software Foundation, Inc.

This file is part of GNU CC.

GNU CC 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 2, or (at your option)
any later version.

GNU CC 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 GNU CC; see the file COPYING.  If not, write to
the Free Software Foundation, 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */


/* This program reads the machine description for the compiler target machine
   and produces a file containing these things:

   1. An array of strings `insn_template' which is indexed by insn code number
   and contains the template for output of that insn,

   2. An array of functions `insn_outfun' which, indexed by the insn code
   number, gives the function that returns a template to use for output of
   that insn.  This is used only in the cases where the template is not
   constant.  These cases are specified by a * or @ at the beginning of the
   template string in the machine description.  They are identified for the
   sake of other parts of the compiler by a zero element in `insn_template'.
  
   3. An array of functions `insn_gen_function' which, indexed
   by insn code number, gives the function to generate a body
   for that pattern, given operands as arguments.

   4. An array of strings `insn_name' which, indexed by insn code number,
   gives the name for that pattern.  Nameless patterns are given a name.

   5. An array of ints `insn_n_operands' which is indexed by insn code number
   and contains the number of distinct operands in the pattern for that insn,

   6. An array of ints `insn_n_dups' which is indexed by insn code number
   and contains the number of match_dup's that appear in the insn's pattern.
   This says how many elements of `recog_dup_loc' are significant
   after an insn has been recognized.

   7. An array of arrays of operand constraint strings,
   `insn_operand_constraint',
   indexed first by insn code number and second by operand number,
   containing the constraint for that operand.

   This array is generated only if register constraints appear in 
   match_operand rtx's.

   8. An array of arrays of chars which indicate which operands of
   which insn patterns appear within ADDRESS rtx's.  This array is
   called `insn_operand_address_p' and is generated only if there
   are *no* register constraints in the match_operand rtx's.

   9. An array of arrays of machine modes, `insn_operand_mode',
   indexed first by insn code number and second by operand number,
   containing the machine mode that that operand is supposed to have.
   Also `insn_operand_strict_low', which is nonzero for operands
   contained in a STRICT_LOW_PART.

   10. An array of arrays of int-valued functions, `insn_operand_predicate',
   indexed first by insn code number and second by operand number,
   containing the match_operand predicate for this operand.

   11. An array of ints, `insn_n_alternatives', that gives the number
   of alternatives in the constraints of each pattern.

The code number of an insn is simply its position in the machine description;
code numbers are assigned sequentially to entries in the description,
starting with code number 0.

Thus, the following entry in the machine description

    (define_insn "clrdf"
      [(set (match_operand:DF 0 "general_operand" "")
            (const_int 0))]
      ""
      "clrd %0")

assuming it is the 25th entry present, would cause
insn_template[24] to be "clrd %0", and insn_n_operands[24] to be 1.
It would not make an case in output_insn_hairy because the template
given in the entry is a constant (it does not start with `*').  */

#include <stdio.h>
#include "hconfig.h"
#include "rtl.h"
#include "obstack.h"

/* No instruction can have more operands than this.
   Sorry for this arbitrary limit, but what machine will
   have an instruction with this many operands?  */

#define MAX_MAX_OPERANDS 40

static struct obstack obstack;
struct obstack *rtl_obstack = &obstack;

#define obstack_chunk_alloc xmalloc
#define obstack_chunk_free free

extern void free ();
extern rtx read_rtx ();

char *xmalloc ();
static void fatal ();
void fancy_abort ();
static void error ();
static void mybcopy ();
static void mybzero ();
static int n_occurrences ();

/* insns in the machine description are assigned sequential code numbers
   that are used by insn-recog.c (produced by genrecog) to communicate
   to insn-output.c (produced by this program).  */

static int next_code_number;

/* This counts all definitions in the md file,
   for the sake of error messages.  */

static int next_index_number;

/* Record in this chain all information that we will output,
   associated with the code number of the insn.  */

struct data
{
  int code_number;
  int index_number;
  char *name;
  char *template;               /* string such as "movl %1,%0" */
  int n_operands;               /* Number of operands this insn recognizes */
  int n_dups;                   /* Number times match_dup appears in pattern */
  int n_alternatives;           /* Number of alternatives in each constraint */
  struct data *next;
  char *constraints[MAX_MAX_OPERANDS];
  /* Number of alternatives in constraints of operand N.  */
  int op_n_alternatives[MAX_MAX_OPERANDS];
  char *predicates[MAX_MAX_OPERANDS];
  char address_p[MAX_MAX_OPERANDS];
  enum machine_mode modes[MAX_MAX_OPERANDS];
  char strict_low[MAX_MAX_OPERANDS];
  char outfun;                  /* Nonzero means this has an output function */
};

/* This variable points to the first link in the chain.  */

struct data *insn_data;

/* Pointer to the last link in the chain, so new elements
   can be added at the end.  */

struct data *end_of_insn_data;

/* Nonzero if any match_operand has a constraint string;
   implies that REGISTER_CONSTRAINTS will be defined
   for this machine description.  */

int have_constraints;

/* Nonzero if some error has occurred.  We will make all errors fatal, but
   might as well continue until we see all of them.  */

static int have_error;

static void
output_prologue ()
{

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

  printf ("#include \"config.h\"\n");
  printf ("#include \"rtl.h\"\n");
  printf ("#include \"regs.h\"\n");
  printf ("#include \"hard-reg-set.h\"\n");
  printf ("#include \"real.h\"\n");
  printf ("#include \"insn-config.h\"\n\n");
  printf ("#include \"conditions.h\"\n");
  printf ("#include \"insn-flags.h\"\n");
  printf ("#include \"insn-attr.h\"\n\n");
  printf ("#include \"insn-codes.h\"\n\n");
  printf ("#include \"recog.h\"\n\n");

  printf ("#include <stdio.h>\n");
  printf ("#include \"output.h\"\n");
}

static void
output_epilogue ()
{
  register struct data *d;

  printf ("\nchar * const insn_template[] =\n  {\n");
  for (d = insn_data; d; d = d->next)
    {
      if (d->template)
        printf ("    \"%s\",\n", d->template);
      else
        printf ("    0,\n");
    }
  printf ("  };\n");

  printf ("\nchar *(*const insn_outfun[])() =\n  {\n");
  for (d = insn_data; d; d = d->next)
    {
      if (d->outfun)
        printf ("    output_%d,\n", d->code_number);
      else
        printf ("    0,\n");
    }
  printf ("  };\n");

  printf ("\nrtx (*const insn_gen_function[]) () =\n  {\n");
  for (d = insn_data; d; d = d->next)
    {
      if (d->name && d->name[0] != '*')
        printf ("    gen_%s,\n", d->name);
      else
        printf ("    0,\n");
    }
  printf ("  };\n");

  printf ("\nchar *insn_name[] =\n  {\n");
  {
    int offset = 0;
    int next;
    char * last_name = 0;
    char * next_name;
    register struct data *n;

    for (n = insn_data, next = 1; n; n = n->next, next++)
      if (n->name)
        {
          next_name = n->name;
          break;
        }

    for (d = insn_data; d; d = d->next)
      {
        if (d->name)
          {
            printf ("    \"%s\",\n", d->name);
            offset = 0;
            last_name = d->name;
            next_name = 0;
            for (n = d->next, next = 1; n; n = n->next, next++)
              if (n->name)
                {
                  next_name = n->name;
                  break;
                }
          }
        else
          {
            offset++;
            if (next_name && (last_name == 0 || offset > next / 2))
              printf ("    \"%s-%d\",\n", next_name, next - offset);
            else
              printf ("    \"%s+%d\",\n", last_name, offset);
          }
      }
  }
  printf ("  };\n");
  printf ("char **insn_name_ptr = insn_name;\n");

  printf ("\nconst int insn_n_operands[] =\n  {\n");
  for (d = insn_data; d; d = d->next)
    printf ("    %d,\n", d->n_operands);
  printf ("  };\n");

  printf ("\nconst int insn_n_dups[] =\n  {\n");
  for (d = insn_data; d; d = d->next)
    printf ("    %d,\n", d->n_dups);
  printf ("  };\n");

  if (have_constraints)
    {
      printf ("\nchar *const insn_operand_constraint[][MAX_RECOG_OPERANDS] =\n  {\n");
      for (d = insn_data; d; d = d->next)
        {
          register int i;
          printf ("    {");
          for (i = 0; i < d->n_operands; i++)
            {
              if (d->constraints[i] == 0)
                printf (" \"\",");
              else
                printf (" \"%s\",", d->constraints[i]);
            }
          if (d->n_operands == 0)
            printf (" 0");
          printf (" },\n");
        }
      printf ("  };\n");
    }
  else
    {
      printf ("\nconst char insn_operand_address_p[][MAX_RECOG_OPERANDS] =\n  {\n");
      for (d = insn_data; d; d = d->next)
        {
          register int i;
          printf ("    {");
          for (i = 0; i < d->n_operands; i++)
            printf (" %d,", d->address_p[i]);
          if (d->n_operands == 0)
            printf (" 0");
          printf (" },\n");
        }
      printf ("  };\n");
    }

  printf ("\nconst enum machine_mode insn_operand_mode[][MAX_RECOG_OPERANDS] =\n  {\n");
  for (d = insn_data; d; d = d->next)
    {
      register int i;
      printf ("    {");
      for (i = 0; i < d->n_operands; i++)
        printf (" %smode,", GET_MODE_NAME (d->modes[i]));
      if (d->n_operands == 0)
        printf (" VOIDmode");
      printf (" },\n");
    }
  printf ("  };\n");

  printf ("\nconst char insn_operand_strict_low[][MAX_RECOG_OPERANDS] =\n  {\n");
  for (d = insn_data; d; d = d->next)
    {
      register int i;
      printf ("    {");
      for (i = 0; i < d->n_operands; i++)
        printf (" %d,", d->strict_low[i]);
      if (d->n_operands == 0)
        printf (" 0");
      printf (" },\n");
    }
  printf ("  };\n");

  {
    /* We need to define all predicates used.  Keep a list of those we
       have defined so far.  There normally aren't very many predicates used,
       so a linked list should be fast enough.  */
    struct predicate { char *name; struct predicate *next; } *predicates = 0;
    struct predicate *p;
    int i;

    printf ("\n");
    for (d = insn_data; d; d = d->next)
      for (i = 0; i < d->n_operands; i++)
        if (d->predicates[i] && d->predicates[i][0])
          {
            for (p = predicates; p; p = p->next)
              if (! strcmp (p->name, d->predicates[i]))
                break;

            if (p == 0)
              {
                printf ("extern int %s ();\n", d->predicates[i]);
                p = (struct predicate *) alloca (sizeof (struct predicate));
                p->name = d->predicates[i];
                p->next = predicates;
                predicates = p;
              }
          }
    
    printf ("\nint (*const insn_operand_predicate[][MAX_RECOG_OPERANDS])() =\n  {\n");
    for (d = insn_data; d; d = d->next)
      {
        printf ("    {");
        for (i = 0; i < d->n_operands; i++)
          printf (" %s,", ((d->predicates[i] && d->predicates[i][0])
                           ? d->predicates[i] : "0"));
        if (d->n_operands == 0)
          printf (" 0");
        printf (" },\n");
      }
    printf ("  };\n");
  }

  printf ("\nconst int insn_n_alternatives[] =\n  {\n");
  for (d = insn_data; d; d = d->next)
    printf ("    %d,\n", d->n_alternatives);
  printf("  };\n");
}

/* scan_operands (X) stores in max_opno the largest operand
   number present in X, if that is larger than the previous
   value of max_opno.  It stores all the constraints in `constraints'
   and all the machine modes in `modes'.

   THIS_ADDRESS_P is nonzero if the containing rtx was an ADDRESS.
   THIS_STRICT_LOW is nonzero if the containing rtx was a STRICT_LOW_PART.  */

static int max_opno;
static int num_dups;
static char *constraints[MAX_MAX_OPERANDS];
static int op_n_alternatives[MAX_MAX_OPERANDS];
static char *predicates[MAX_MAX_OPERANDS];
static char address_p[MAX_MAX_OPERANDS];
static enum machine_mode modes[MAX_MAX_OPERANDS];
static char strict_low[MAX_MAX_OPERANDS];
static char seen[MAX_MAX_OPERANDS];

static void
scan_operands (part, this_address_p, this_strict_low)
     rtx part;
     int this_address_p;
     int this_strict_low;
{
  register int i, j;
  register char *format_ptr;
  int opno;

  if (part == 0)
    return;

  switch (GET_CODE (part))
    {
    case MATCH_OPERAND:
      opno = XINT (part, 0);
      if (opno > max_opno)
        max_opno = opno;
      if (max_opno >= MAX_MAX_OPERANDS)
        {
          error ("Too many operands (%d) in definition %d.\n",
                 max_opno + 1, next_index_number);
          return;
        }
      if (seen[opno])
        error ("Definition %d specified operand number %d more than once.\n",
               next_index_number, opno);
      seen[opno] = 1;
      modes[opno] = GET_MODE (part);
      strict_low[opno] = this_strict_low;
      predicates[opno] = XSTR (part, 1);
      constraints[opno] = XSTR (part, 2);
      if (XSTR (part, 2) != 0 && *XSTR (part, 2) != 0)
        {
          op_n_alternatives[opno] = n_occurrences (',', XSTR (part, 2)) + 1;
          have_constraints = 1;
        }
      address_p[opno] = this_address_p;
      return;

    case MATCH_SCRATCH:
      opno = XINT (part, 0);
      if (opno > max_opno)
        max_opno = opno;
      if (max_opno >= MAX_MAX_OPERANDS)
        {
          error ("Too many operands (%d) in definition %d.\n",
                 max_opno + 1, next_index_number);
          return;
        }
      if (seen[opno])
        error ("Definition %d specified operand number %d more than once.\n",
               next_index_number, opno);
      seen[opno] = 1;
      modes[opno] = GET_MODE (part);
      strict_low[opno] = 0;
      predicates[opno] = "scratch_operand";
      constraints[opno] = XSTR (part, 1);
      if (XSTR (part, 1) != 0 && *XSTR (part, 1) != 0)
        {
          op_n_alternatives[opno] = n_occurrences (',', XSTR (part, 1)) + 1;
          have_constraints = 1;
        }
      address_p[opno] = 0;
      return;

    case MATCH_OPERATOR:
    case MATCH_PARALLEL:
      opno = XINT (part, 0);
      if (opno > max_opno)
        max_opno = opno;
      if (max_opno >= MAX_MAX_OPERANDS)
        {
          error ("Too many operands (%d) in definition %d.\n",
                 max_opno + 1, next_index_number);
          return;
        }
      if (seen[opno])
        error ("Definition %d specified operand number %d more than once.\n",
               next_index_number, opno);
      seen[opno] = 1;
      modes[opno] = GET_MODE (part);
      strict_low[opno] = 0;
      predicates[opno] = XSTR (part, 1);
      constraints[opno] = 0;
      address_p[opno] = 0;
      for (i = 0; i < XVECLEN (part, 2); i++)
        scan_operands (XVECEXP (part, 2, i), 0, 0);
      return;

    case MATCH_DUP:
    case MATCH_OP_DUP:
    case MATCH_PAR_DUP:
      ++num_dups;
      return;

    case ADDRESS:
      scan_operands (XEXP (part, 0), 1, 0);
      return;

    case STRICT_LOW_PART:
      scan_operands (XEXP (part, 0), 0, 1);
      return;
    }

  format_ptr = GET_RTX_FORMAT (GET_CODE (part));

  for (i = 0; i < GET_RTX_LENGTH (GET_CODE (part)); i++)
    switch (*format_ptr++)
      {
      case 'e':
        scan_operands (XEXP (part, i), 0, 0);
        break;
      case 'E':
        if (XVEC (part, i) != NULL)
          for (j = 0; j < XVECLEN (part, i); j++)
            scan_operands (XVECEXP (part, i, j), 0, 0);
        break;
      }
}

/* Process an assembler template from a define_insn or a define_peephole.
   It is either the assembler code template, a list of assembler code
   templates, or C code to generate the assembler code template.  */

static void
process_template (d, template)
    struct data *d;
    char *template;
{
  register char *cp;
  register int i;

  /* We need to consider only the instructions whose assembler code template
     starts with a * or @.  These are the ones where C code is run to decide
     on a template to use.  So for all others just return now.  */

  if (template[0] != '*' && template[0] != '@')
    {
      d->template = template;
      d->outfun = 0;
      return;
    }

  d->template = 0;
  d->outfun = 1;

  printf ("\nstatic char *\n");
  printf ("output_%d (operands, insn)\n", d->code_number);
  printf ("     rtx *operands;\n");
  printf ("     rtx insn;\n");
  printf ("{\n");

  /* If the assembler code template starts with a @ it is a newline-separated
     list of assembler code templates, one for each alternative.  So produce
     a routine to select the correct one.  */

  if (template[0] == '@')
    {

      printf ("  static /*const*/ char *const strings_%d[] = {\n",
              d->code_number);

      for (i = 0, cp = &template[1]; *cp; )
        {
          while (*cp == '\n' || *cp == ' ' || *cp== '\t')
            cp++;

          printf ("    \"");
          while (*cp != '\n' && *cp != '\0')
            putchar (*cp++);

          printf ("\",\n");
          i++;
        }

      printf ("  };\n");
      printf ("  return strings_%d[which_alternative];\n", d->code_number);

      if (i != d->n_alternatives)
        fatal ("Insn pattern %d has %d alternatives but %d assembler choices",
               d->index_number, d->n_alternatives, i);

    }
  else
    {
       /* The following is done in a funny way to get around problems in
          VAX-11 "C" on VMS.  It is the equivalent of:
                printf ("%s\n", &template[1])); */
      cp = &template[1];
      while (*cp) putchar (*cp++);
      putchar ('\n');
    }

  printf ("}\n");
}

/* Check insn D for consistency in number of constraint alternatives.  */

static void
validate_insn_alternatives (d)
     struct data *d;
{
  register int n = 0, start;
  /* Make sure all the operands have the same number of
     alternatives in their constraints.
     Let N be that number.  */
  for (start = 0; start < d->n_operands; start++)
    if (d->op_n_alternatives[start] > 0)
      {
        if (n == 0)
          n = d->op_n_alternatives[start];
        else if (n != d->op_n_alternatives[start])
          error ("wrong number of alternatives in operand %d of insn number %d",
                 start, d->index_number);
      }
  /* Record the insn's overall number of alternatives.  */
  d->n_alternatives = n;
}

/* Look at a define_insn just read.  Assign its code number.
   Record on insn_data the template and the number of arguments.
   If the insn has a hairy output action, output a function for now.  */

static void
gen_insn (insn)
     rtx insn;
{
  register struct data *d = (struct data *) xmalloc (sizeof (struct data));
  register int i;

  d->code_number = next_code_number++;
  d->index_number = next_index_number;
  if (XSTR (insn, 0)[0])
    d->name = XSTR (insn, 0);
  else
    d->name = 0;

  /* Build up the list in the same order as the insns are seen
     in the machine description.  */
  d->next = 0;
  if (end_of_insn_data)
    end_of_insn_data->next = d;
  else
    insn_data = d;

  end_of_insn_data = d;

  max_opno = -1;
  num_dups = 0;

  mybzero (constraints, sizeof constraints);
  mybzero (op_n_alternatives, sizeof op_n_alternatives);
  mybzero (predicates, sizeof predicates);
  mybzero (address_p, sizeof address_p);
  mybzero (modes, sizeof modes);
  mybzero (strict_low, sizeof strict_low);
  mybzero (seen, sizeof seen);

  for (i = 0; i < XVECLEN (insn, 1); i++)
    scan_operands (XVECEXP (insn, 1, i), 0, 0);

  d->n_operands = max_opno + 1;
  d->n_dups = num_dups;

  mybcopy (constraints, d->constraints, sizeof constraints);
  mybcopy (op_n_alternatives, d->op_n_alternatives, sizeof op_n_alternatives);
  mybcopy (predicates, d->predicates, sizeof predicates);
  mybcopy (address_p, d->address_p, sizeof address_p);
  mybcopy (modes, d->modes, sizeof modes);
  mybcopy (strict_low, d->strict_low, sizeof strict_low);

  validate_insn_alternatives (d);
  process_template (d, XSTR (insn, 3));
}

/* Look at a define_peephole just read.  Assign its code number.
   Record on insn_data the template and the number of arguments.
   If the insn has a hairy output action, output it now.  */

static void
gen_peephole (peep)
     rtx peep;
{
  register struct data *d = (struct data *) xmalloc (sizeof (struct data));
  register int i;

  d->code_number = next_code_number++;
  d->index_number = next_index_number;
  d->name = 0;

  /* Build up the list in the same order as the insns are seen
     in the machine description.  */
  d->next = 0;
  if (end_of_insn_data)
    end_of_insn_data->next = d;
  else
    insn_data = d;

  end_of_insn_data = d;

  max_opno = -1;
  mybzero (constraints, sizeof constraints);
  mybzero (op_n_alternatives, sizeof op_n_alternatives);
  mybzero (predicates, sizeof predicates);
  mybzero (address_p, sizeof address_p);
  mybzero (modes, sizeof modes);
  mybzero (strict_low, sizeof strict_low);
  mybzero (seen, sizeof seen);

  /* Get the number of operands by scanning all the
     patterns of the peephole optimizer.
     But ignore all the rest of the information thus obtained.  */
  for (i = 0; i < XVECLEN (peep, 0); i++)
    scan_operands (XVECEXP (peep, 0, i), 0, 0);

  d->n_operands = max_opno + 1;
  d->n_dups = 0;

  mybcopy (constraints, d->constraints, sizeof constraints);
  mybcopy (op_n_alternatives, d->op_n_alternatives, sizeof op_n_alternatives);
  mybzero (d->predicates, sizeof predicates);
  mybzero (d->address_p, sizeof address_p);
  mybzero (d->modes, sizeof modes);
  mybzero (d->strict_low, sizeof strict_low);

  validate_insn_alternatives (d);
  process_template (d, XSTR (peep, 2));
}

/* Process a define_expand just read.  Assign its code number,
   only for the purposes of `insn_gen_function'.  */

static void
gen_expand (insn)
     rtx insn;
{
  register struct data *d = (struct data *) xmalloc (sizeof (struct data));
  register int i;

  d->code_number = next_code_number++;
  d->index_number = next_index_number;
  if (XSTR (insn, 0)[0])
    d->name = XSTR (insn, 0);
  else
    d->name = 0;

  /* Build up the list in the same order as the insns are seen
     in the machine description.  */
  d->next = 0;
  if (end_of_insn_data)
    end_of_insn_data->next = d;
  else
    insn_data = d;

  end_of_insn_data = d;

  max_opno = -1;
  num_dups = 0;

  /* Scan the operands to get the specified predicates and modes,
     since expand_binop needs to know them.  */

  mybzero (constraints, sizeof constraints);
  mybzero (op_n_alternatives, sizeof op_n_alternatives);
  mybzero (predicates, sizeof predicates);
  mybzero (address_p, sizeof address_p);
  mybzero (modes, sizeof modes);
  mybzero (strict_low, sizeof strict_low);
  mybzero (seen, sizeof seen);

  if (XVEC (insn, 1))
    for (i = 0; i < XVECLEN (insn, 1); i++)
      scan_operands (XVECEXP (insn, 1, i), 0, 0);

  d->n_operands = max_opno + 1;
  d->n_dups = num_dups;

  mybcopy (constraints, d->constraints, sizeof constraints);
  mybcopy (op_n_alternatives, d->op_n_alternatives, sizeof op_n_alternatives);
  mybcopy (predicates, d->predicates, sizeof predicates);
  mybcopy (address_p, d->address_p, sizeof address_p);
  mybcopy (modes, d->modes, sizeof modes);
  mybcopy (strict_low, d->strict_low, sizeof strict_low);

  d->template = 0;
  d->outfun = 0;
  validate_insn_alternatives (d);
}

/* Process a define_split just read.  Assign its code number,
   only for reasons of consistency and to simplify genrecog.  */


static void
gen_split (split)
     rtx split;
{
  register struct data *d = (struct data *) xmalloc (sizeof (struct data));
  register int i;

  d->code_number = next_code_number++;
  d->index_number = next_index_number;
  d->name = 0;

  /* Build up the list in the same order as the insns are seen
     in the machine description.  */
  d->next = 0;
  if (end_of_insn_data)
    end_of_insn_data->next = d;
  else
    insn_data = d;

  end_of_insn_data = d;

  max_opno = -1;
  num_dups = 0;

  mybzero (constraints, sizeof constraints);
  mybzero (op_n_alternatives, sizeof op_n_alternatives);
  mybzero (predicates, sizeof predicates);
  mybzero (address_p, sizeof address_p);
  mybzero (modes, sizeof modes);
  mybzero (strict_low, sizeof strict_low);
  mybzero (seen, sizeof seen);

  /* Get the number of operands by scanning all the
     patterns of the split patterns.
     But ignore all the rest of the information thus obtained.  */
  for (i = 0; i < XVECLEN (split, 0); i++)
    scan_operands (XVECEXP (split, 0, i), 0, 0);

  d->n_operands = max_opno + 1;

  mybzero (d->constraints, sizeof constraints);
  mybzero (d->op_n_alternatives, sizeof op_n_alternatives);
  mybzero (d->predicates, sizeof predicates);
  mybzero (d->address_p, sizeof address_p);
  mybzero (d->modes, sizeof modes);
  mybzero (d->strict_low, sizeof strict_low);

  d->n_dups = 0;
  d->n_alternatives = 0;
  d->template = 0;
  d->outfun = 0;
}

char *
xmalloc (size)
     unsigned size;
{
  register char *val = (char *) malloc (size);

  if (val == 0)
    fatal ("virtual memory exhausted");
  return val;
}

char *
xrealloc (ptr, size)
     char *ptr;
     unsigned size;
{
  char *result = (char *) realloc (ptr, size);
  if (!result)
    fatal ("virtual memory exhausted");
  return result;
}

static void
mybzero (b, length)
     register char *b;
     register unsigned length;
{
  while (length-- > 0)
    *b++ = 0;
}

static void
mybcopy (b1, b2, length)
     register char *b1;
     register char *b2;
     register unsigned length;
{
  while (length-- > 0)
    *b2++ = *b1++;
}

static void
fatal (s, a1, a2, a3, a4)
     char *s;
{
  fprintf (stderr, "genoutput: ");
  fprintf (stderr, s, a1, a2, a3, a4);
  fprintf (stderr, "\n");
  exit (FATAL_EXIT_CODE);
}

/* More 'friendly' abort that prints the line and file.
   config.h can #define abort fancy_abort if you like that sort of thing.  */

void
fancy_abort ()
{
  fatal ("Internal gcc abort.");
}

static void
error (s, a1, a2)
     char *s;
{
  fprintf (stderr, "genoutput: ");
  fprintf (stderr, s, a1, a2);
  fprintf (stderr, "\n");

  have_error = 1;
}

int
main (argc, argv)
     int argc;
     char **argv;
{
  rtx desc;
  FILE *infile;
  register int c;

  obstack_init (rtl_obstack);

  if (argc <= 1)
    fatal ("No input file name.");

  infile = fopen (argv[1], "r");
  if (infile == 0)
    {
      perror (argv[1]);
      exit (FATAL_EXIT_CODE);
    }

  init_rtl ();

  output_prologue ();
  next_code_number = 0;
  next_index_number = 0;
  have_constraints = 0;

  /* Read the machine description.  */

  while (1)
    {
      c = read_skip_spaces (infile);
      if (c == EOF)
        break;
      ungetc (c, infile);

      desc = read_rtx (infile);
      if (GET_CODE (desc) == DEFINE_INSN)
        gen_insn (desc);
      if (GET_CODE (desc) == DEFINE_PEEPHOLE)
        gen_peephole (desc);
      if (GET_CODE (desc) == DEFINE_EXPAND)
        gen_expand (desc);
      if (GET_CODE (desc) == DEFINE_SPLIT)
        gen_split (desc);
      next_index_number++;
    }

  output_epilogue ();

  fflush (stdout);
  exit (ferror (stdout) != 0 || have_error
        ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE);

  /* NOTREACHED */
  return 0;
}

static int
n_occurrences (c, s)
     int c;
     char *s;
{
  int n = 0;
  while (*s)
    n += (*s++ == c);
  return n;
}