genattrtab.c

早期freebsd实现

	}
    }

  /* Compute the mask of function units used.  Initially, the unitsmask is
     zero.   Set up a conditional to compute each unit's contribution.  */
  unitsmask = make_numeric_value (0);
  newexp = rtx_alloc (IF_THEN_ELSE);
  XEXP (newexp, 2) = make_numeric_value (0);

  /* Merge each function unit into the unit mask attributes.  */
  for (unit = units; unit; unit = unit->next)
    {
      XEXP (newexp, 0) = unit->condexp;
      XEXP (newexp, 1) = make_numeric_value (1 << unit->num);
      unitsmask = operate_exp (OR_OP, unitsmask, newexp);
    }

  /* Simplify the unit mask expression, encode it, and make an attribute
     for the function_units_used function.  */
  unitsmask = simplify_by_exploding (unitsmask);
  unitsmask = encode_units_mask (unitsmask);
  make_internal_attr ("*function_units_used", unitsmask, 2);

  /* Create an array of ops for each unit.  Add an extra unit for the
     result_ready_cost function that has the ops of all other units.  */
  unit_ops = (struct function_unit_op ***)
    alloca ((num_units + 1) * sizeof (struct function_unit_op **));
  unit_num = (struct function_unit **)
    alloca ((num_units + 1) * sizeof (struct function_unit *));

  unit_num[num_units] = unit = (struct function_unit *)
    alloca (sizeof (struct function_unit));
  unit->num = num_units;
  unit->num_opclasses = 0;

  for (unit = units; unit; unit = unit->next)
    {
      unit_num[num_units]->num_opclasses += unit->num_opclasses;
      unit_num[unit->num] = unit;
      unit_ops[unit->num] = op_array = (struct function_unit_op **)
	alloca (unit->num_opclasses * sizeof (struct function_unit_op *));

      for (op = unit->ops; op; op = op->next)
	op_array[op->num] = op;
    }

  /* Compose the array of ops for the extra unit.  */
  unit_ops[num_units] = op_array = (struct function_unit_op **)
    alloca (unit_num[num_units]->num_opclasses
	    * sizeof (struct function_unit_op *));

  for (unit = units, i = 0; unit; i += unit->num_opclasses, unit = unit->next)
    bcopy (unit_ops[unit->num], &op_array[i],
	   unit->num_opclasses * sizeof (struct function_unit_op *));

  /* Compute the ready cost function for each unit by computing the
     condition for each non-default value.  */
  for (u = 0; u <= num_units; u++)
    {
      rtx orexp;
      int value;

      unit = unit_num[u];
      op_array = unit_ops[unit->num];
      num = unit->num_opclasses;

      /* Sort the array of ops into increasing ready cost order.  */
      for (i = 0; i < num; i++)
	for (j = num - 1; j > i; j--)
	  if (op_array[j-1]->ready < op_array[j]->ready)
	    {
	      op = op_array[j];
	      op_array[j] = op_array[j-1];
	      op_array[j-1] = op;
	    }

      /* Determine how many distinct non-default ready cost values there
	 are.  We use a default ready cost value of 1.  */
      nvalues = 0; value = 1;
      for (i = num - 1; i >= 0; i--)
	if (op_array[i]->ready > value)
	  {
	    value = op_array[i]->ready;
	    nvalues++;
	  }

      if (nvalues == 0)
	readycost = make_numeric_value (1);
      else
	{
	  /* Construct the ready cost expression as a COND of each value from
	     the largest to the smallest.  */
	  readycost = rtx_alloc (COND);
	  XVEC (readycost, 0) = rtvec_alloc (nvalues * 2);
	  XEXP (readycost, 1) = make_numeric_value (1);

	  nvalues = 0; orexp = false_rtx; value = op_array[0]->ready;
	  for (i = 0; i < num; i++)
	    {
	      op = op_array[i];
	      if (op->ready <= 1)
		break;
	      else if (op->ready == value)
		orexp = insert_right_side (IOR, orexp, op->condexp, -2);
	      else
		{
		  XVECEXP (readycost, 0, nvalues * 2) = orexp;
		  XVECEXP (readycost, 0, nvalues * 2 + 1)
		    = make_numeric_value (value);
		  nvalues++;
		  value = op->ready;
		  orexp = op->condexp;
		}
	    }
	  XVECEXP (readycost, 0, nvalues * 2) = orexp;
	  XVECEXP (readycost, 0, nvalues * 2 + 1) = make_numeric_value (value);
	}

      if (u < num_units)
	{
	  rtx max_blockage = 0, min_blockage = 0;

	  /* Simplify the readycost expression by only considering insns
	     that use the unit.  */
	  readycost = simplify_knowing (readycost, unit->condexp);

	  /* Determine the blockage cost the executing insn (E) given
	     the candidate insn (C).  This is the maximum of the issue
	     delay, the pipeline delay, and the simultaneity constraint.
	     Each function_unit_op represents the characteristics of the
	     candidate insn, so in the expressions below, C is a known
	     term and E is an unknown term.

	     The issue delay function for C is op->issue_exp and is used to
	     write the `<name>_unit_conflict_cost' function.  Symbolicly
	     this is "ISSUE-DELAY (E,C)".

	     The pipeline delay results form the FIFO constraint on the
	     function unit and is "READY-COST (E) + 1 - READY-COST (C)".

	     The simultaneity constraint is based on how long it takes to
	     fill the unit given the minimum issue delay.  FILL-TIME is the
	     constant "MIN (ISSUE-DELAY (*,*)) * (SIMULTANEITY - 1)", and
	     the simultaneity constraint is "READY-COST (E) - FILL-TIME"
	     if SIMULTANEITY is non-zero and zero otherwise.

	     Thus, BLOCKAGE (E,C) when SIMULTANEITY is zero is

	         MAX (ISSUE-DELAY (E,C),
		      READY-COST (E) - (READY-COST (C) - 1))

	     and otherwise

	         MAX (ISSUE-DELAY (E,C),
		      READY-COST (E) - (READY-COST (C) - 1),
		      READY-COST (E) - FILL-TIME)

	     The `<name>_unit_blockage' function is computed by determining
	     this value for each candidate insn.  As these values are
	     computed, we also compute the upper and lower bounds for
	     BLOCKAGE (E,*).  These are combined to form the function
	     `<name>_unit_blockage_range'.  Finally, the maximum blockage
	     cost, MAX (BLOCKAGE (*,*)), is computed.  */

	  for (op = unit->ops; op; op = op->next)
	    {
	      rtx blockage = readycost;
	      int delay = op->ready - 1;

	      if (unit->simultaneity != 0)
		delay = MIN (delay, ((unit->simultaneity - 1)
				     * unit->issue_delay.min));

	      if (delay > 0)
		blockage = operate_exp (POS_MINUS_OP, blockage,
					make_numeric_value (delay));

	      blockage = operate_exp (MAX_OP, blockage, op->issue_exp);
	      blockage = simplify_knowing (blockage, unit->condexp);

	      /* Add this op's contribution to MAX (BLOCKAGE (E,*)) and
		 MIN (BLOCKAGE (E,*)).  */
	      if (max_blockage == 0)
		max_blockage = min_blockage = blockage;
	      else
		{
		  max_blockage
		    = simplify_knowing (operate_exp (MAX_OP, max_blockage,
						     blockage),
					unit->condexp);
		  min_blockage
		    = simplify_knowing (operate_exp (MIN_OP, min_blockage,
						     blockage),
					unit->condexp);
		}

	      /* Make an attribute for use in the blockage function.  */
	      str = attr_printf (strlen (unit->name) + sizeof ("*_block_") + MAX_DIGITS,
				 "*%s_block_%d", unit->name, op->num);
	      make_internal_attr (str, blockage, 1);
	    }

	  /* Record MAX (BLOCKAGE (*,*)).  */
	  unit->max_blockage = max_attr_value (max_blockage);

	  /* See if the upper and lower bounds of BLOCKAGE (E,*) are the
	     same.  If so, the blockage function carries no additional
	     information and is not written.  */
	  newexp = operate_exp (EQ_OP, max_blockage, min_blockage);
	  newexp = simplify_knowing (newexp, unit->condexp);
	  unit->needs_blockage_function
	    = (GET_CODE (newexp) != CONST_STRING
	       || atoi (XSTR (newexp, 0)) != 1);

	  /* If the all values of BLOCKAGE (E,C) have the same value,
	     neither blockage function is written.  */	  
	  unit->needs_range_function
	    = (unit->needs_blockage_function
	       || GET_CODE (max_blockage) != CONST_STRING);

	  if (unit->needs_range_function)
	    {
	      /* Compute the blockage range function and make an attribute
		 for writing it's value.  */
	      newexp = operate_exp (RANGE_OP, min_blockage, max_blockage);
	      newexp = simplify_knowing (newexp, unit->condexp);

	      str = attr_printf (strlen (unit->name) + sizeof ("*_unit_blockage_range"),
				 "*%s_unit_blockage_range", unit->name);
	      make_internal_attr (str, newexp, 4);
	    }

	  str = attr_printf (strlen (unit->name) + sizeof ("*_unit_ready_cost"),
			     "*%s_unit_ready_cost", unit->name);
	}
      else
	str = "*result_ready_cost";

      /* Make an attribute for the ready_cost function.  Simplifying
	 further with simplify_by_exploding doesn't win.  */
      make_internal_attr (str, readycost, 0);
    }

  /* For each unit that requires a conflict cost function, make an attribute
     that maps insns to the operation number.  */
  for (unit = units; unit; unit = unit->next)
    {
      rtx caseexp;

      if (! unit->needs_conflict_function
	  && ! unit->needs_blockage_function)
	continue;

      caseexp = rtx_alloc (COND);
      XVEC (caseexp, 0) = rtvec_alloc ((unit->num_opclasses - 1) * 2);

      for (op = unit->ops; op; op = op->next)
	{
	  /* Make our adjustment to the COND being computed.  If we are the
	     last operation class, place our values into the default of the
	     COND.  */
	  if (op->num == unit->num_opclasses - 1)
	    {
	      XEXP (caseexp, 1) = make_numeric_value (op->num);
	    }
	  else
	    {
	      XVECEXP (caseexp, 0, op->num * 2) = op->condexp;
	      XVECEXP (caseexp, 0, op->num * 2 + 1)
		= make_numeric_value (op->num);
	    }
	}

      /* Simplifying caseexp with simplify_by_exploding doesn't win.  */
      str = attr_printf (strlen (unit->name) + sizeof ("*_cases"),
			 "*%s_cases", unit->name);
      make_internal_attr (str, caseexp, 1);
    }
}

/* Simplify EXP given KNOWN_TRUE.  */

static rtx
simplify_knowing (exp, known_true)
     rtx exp, known_true;
{
  if (GET_CODE (exp) != CONST_STRING)
    {
      exp = attr_rtx (IF_THEN_ELSE, known_true, exp,
		      make_numeric_value (max_attr_value (exp)));
      exp = simplify_by_exploding (exp);
    }
  return exp;
}

/* Translate the CONST_STRING expressions in X to change the encoding of
   value.  On input, the value is a bitmask with a one bit for each unit
   used; on output, the value is the unit number (zero based) if one
   and only one unit is used or the one's compliment of the bitmask.  */

static rtx
encode_units_mask (x)
     rtx x;
{
  register int i;
  register int j;
  register enum rtx_code code;
  register char *fmt;

  code = GET_CODE (x);

  switch (code)
    {
    case CONST_STRING:
      i = atoi (XSTR (x, 0));
      if (i < 0)
	abort (); /* The sign bit encodes a one's compliment mask.  */
      else if (i != 0 && i == (i & -i))
	/* Only one bit is set, so yield that unit number.  */
	for (j = 0; (i >>= 1) != 0; j++)
	  ;
      else
	j = ~i;
      return attr_rtx (CONST_STRING, attr_printf (MAX_DIGITS, "%d", j));

    case REG:
    case QUEUED:
    case CONST_INT:
    case CONST_DOUBLE:
    case SYMBOL_REF:
    case CODE_LABEL:
    case PC:
    case CC0:
    case EQ_ATTR:
      return x;
    }

  /* Compare the elements.  If any pair of corresponding elements
     fail to match, return 0 for the whole things.  */

  fmt = GET_RTX_FORMAT (code);
  for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
    {
      switch (fmt[i])
	{
	case 'V':
	case 'E':
	  for (j = 0; j < XVECLEN (x, i); j++)
	    XVECEXP (x, i, j) = encode_units_mask (XVECEXP (x, i, j));
	  break;

	case 'e':
	  XEXP (x, i) = encode_units_mask (XEXP (x, i));
	  break;
	}
    }
  return x;
}

/* Once all attributes and insns have been read and checked, we construct for
   each attribute value a list of all the insns that have that value for
   the attribute.  */

static void
fill_attr (attr)
     struct attr_desc *attr;
{
  struct attr_value *av;
  struct insn_ent *ie;
  struct insn_def *id;
  int i;
  rtx value;

  /* Don't fill constant attributes.  The value is independent of
     any particular insn.  */
  if (attr->is_const)
    return;

  for (id = defs; id; id = id->next)
    {
      /* If no value is specified for this insn for this attribute, use the
	 default.  */
      value = NULL;
      if (XVEC (id->def, id->vec_idx))
	for (i = 0; i < XVECLEN (id->def, id->vec_idx); i++)
	  if (! strcmp (XSTR (XEXP (XVECEXP (id->def, id->vec_idx, i), 0), 0), 
			attr->name))
	    value = XEXP (XVECEXP (id->def, id->vec_idx, i), 1);

      if (value == NULL)
	av = attr->default_val;
      else
	av = get_attr_value (value, attr, id->insn_code);

      ie = (struct insn_ent *) oballoc (sizeof (struct insn_ent));
      ie->insn_code = id->insn_code;
      ie->insn_index = id->insn_code;
      insert_insn_ent (av, ie);
    }
}

/* Given an expression EXP, see if it is a COND or IF_THEN_ELSE that has a
   test that checks relative positions of insns (uses MATCH_DUP or PC).
   If so, replace it with what is obtained by passing the expression to
   ADDRESS_FN.  If not but it is a COND or IF_THEN_ELSE, call this routine
   recursively on each value (including the default value).  Otherwise,
   return the value returned by NO_ADDRESS_FN applied to EXP.  */

static rtx
substitute_address (exp, no_address_fn, address_fn)
     rtx exp;
     rtx (*no_address_fn) ();
     rtx (*address_fn) ();
{
  int i;
  rtx newexp;

  if (GET_CODE (exp) == COND)
    {
      /* See if any tests use addresses.  */
      address_used = 0;
      for (i = 0; i < XVECLEN (exp, 0); i += 2)
	walk_attr_value (XVECEXP (exp, 0, i));

      if (address_used)
	return (*address_fn) (exp);

      /* Make a new copy of this COND, replacing each element.  */
      newexp = rtx_alloc (COND);
      XVEC (newexp, 0) = rtvec_alloc (XVECLEN (exp, 0));
      for (i = 0; i < XVECLEN (exp, 0); i += 2)
	{
	  XVECEXP (newexp, 0, i) = XVECEXP (exp, 0, i);
	  XVECEXP (newexp, 0, i + 1)
	    = substitute_address (XVECEXP (exp, 0, i + 1),
				  no_address_fn, address_fn);
	}

      XEXP (newexp