genattrtab.c

gcc库的原代码,对编程有很大帮助.

static void gen_unit		PROTO((rtx));
static void write_test_expr	PROTO((rtx, int));
static int max_attr_value	PROTO((rtx));
static void walk_attr_value	PROTO((rtx));
static void write_attr_get	PROTO((struct attr_desc *));
static rtx eliminate_known_true PROTO((rtx, rtx, int, int));
static void write_attr_set	PROTO((struct attr_desc *, int, rtx, char *,
				       char *, rtx, int, int));
static void write_attr_case	PROTO((struct attr_desc *, struct attr_value *,
				       int, char *, char *, int, rtx));
static void write_attr_valueq	PROTO((struct attr_desc *, char *));
static void write_attr_value	PROTO((struct attr_desc *, rtx));
static void write_upcase	PROTO((char *));
static void write_indent	PROTO((int));
static void write_eligible_delay PROTO((char *));
static void write_function_unit_info PROTO((void));
static void write_complex_function PROTO((struct function_unit *, char *,
					  char *));
static int n_comma_elts		PROTO((char *));
static char *next_comma_elt	PROTO((char **));
static struct attr_desc *find_attr PROTO((char *, int));
static void make_internal_attr	PROTO((char *, rtx, int));
static struct attr_value *find_most_used  PROTO((struct attr_desc *));
static rtx find_single_value	PROTO((struct attr_desc *));
static rtx make_numeric_value	PROTO((int));
static void extend_range	PROTO((struct range *, int, int));
char *xrealloc			PROTO((char *, unsigned));
char *xmalloc			PROTO((unsigned));

#define oballoc(size) obstack_alloc (hash_obstack, size)


/* Hash table for sharing RTL and strings.  */

/* Each hash table slot is a bucket containing a chain of these structures.
   Strings are given negative hash codes; RTL expressions are given positive
   hash codes.  */

struct attr_hash
{
  struct attr_hash *next;	/* Next structure in the bucket.  */
  int hashcode;			/* Hash code of this rtx or string.  */
  union
    {
      char *str;		/* The string (negative hash codes) */
      rtx rtl;			/* or the RTL recorded here.  */
    } u;
};

/* Now here is the hash table.  When recording an RTL, it is added to
   the slot whose index is the hash code mod the table size.  Note
   that the hash table is used for several kinds of RTL (see attr_rtx)
   and for strings.  While all these live in the same table, they are
   completely independent, and the hash code is computed differently
   for each.  */

#define RTL_HASH_SIZE 4093
struct attr_hash *attr_hash_table[RTL_HASH_SIZE];

/* Here is how primitive or already-shared RTL's hash
   codes are made.  */
#define RTL_HASH(RTL) ((HOST_WIDE_INT) (RTL) & 0777777)

/* Add an entry to the hash table for RTL with hash code HASHCODE.  */

static void
attr_hash_add_rtx (hashcode, rtl)
     int hashcode;
     rtx rtl;
{
  register struct attr_hash *h;

  h = (struct attr_hash *) obstack_alloc (hash_obstack,
					  sizeof (struct attr_hash));
  h->hashcode = hashcode;
  h->u.rtl = rtl;
  h->next = attr_hash_table[hashcode % RTL_HASH_SIZE];
  attr_hash_table[hashcode % RTL_HASH_SIZE] = h;
}

/* Add an entry to the hash table for STRING with hash code HASHCODE.  */

static void
attr_hash_add_string (hashcode, str)
     int hashcode;
     char *str;
{
  register struct attr_hash *h;

  h = (struct attr_hash *) obstack_alloc (hash_obstack,
					  sizeof (struct attr_hash));
  h->hashcode = -hashcode;
  h->u.str = str;
  h->next = attr_hash_table[hashcode % RTL_HASH_SIZE];
  attr_hash_table[hashcode % RTL_HASH_SIZE] = h;
}

/* Generate an RTL expression, but avoid duplicates.
   Set the RTX_INTEGRATED_P flag for these permanent objects.

   In some cases we cannot uniquify; then we return an ordinary
   impermanent rtx with RTX_INTEGRATED_P clear.

   Args are like gen_rtx, but without the mode:

   rtx attr_rtx (code, [element1, ..., elementn])  */

/*VARARGS1*/
static rtx
attr_rtx VPROTO((enum rtx_code code, ...))
{
#ifndef __STDC__
  enum rtx_code code;
#endif
  va_list p;
  register int i;		/* Array indices...			*/
  register char *fmt;		/* Current rtx's format...		*/
  register rtx rt_val;		/* RTX to return to caller...		*/
  int hashcode;
  register struct attr_hash *h;
  struct obstack *old_obstack = rtl_obstack;

  VA_START (p, code);

#ifndef __STDC__
  code = va_arg (p, enum rtx_code);
#endif

  /* For each of several cases, search the hash table for an existing entry.
     Use that entry if one is found; otherwise create a new RTL and add it
     to the table.  */

  if (GET_RTX_CLASS (code) == '1')
    {
      rtx arg0 = va_arg (p, rtx);

      /* A permanent object cannot point to impermanent ones.  */
      if (! RTX_INTEGRATED_P (arg0))
	{
	  rt_val = rtx_alloc (code);
	  XEXP (rt_val, 0) = arg0;
	  va_end (p);
	  return rt_val;
	}

      hashcode = ((HOST_WIDE_INT) code + RTL_HASH (arg0));
      for (h = attr_hash_table[hashcode % RTL_HASH_SIZE]; h; h = h->next)
	if (h->hashcode == hashcode
	    && GET_CODE (h->u.rtl) == code
	    && XEXP (h->u.rtl, 0) == arg0)
	  goto found;

      if (h == 0)
	{
	  rtl_obstack = hash_obstack;
	  rt_val = rtx_alloc (code);
	  XEXP (rt_val, 0) = arg0;
	}
    }
  else if (GET_RTX_CLASS (code) == 'c'
	   || GET_RTX_CLASS (code) == '2'
	   || GET_RTX_CLASS (code) == '<')
    {
      rtx arg0 = va_arg (p, rtx);
      rtx arg1 = va_arg (p, rtx);

      /* A permanent object cannot point to impermanent ones.  */
      if (! RTX_INTEGRATED_P (arg0) || ! RTX_INTEGRATED_P (arg1))
	{
	  rt_val = rtx_alloc (code);
	  XEXP (rt_val, 0) = arg0;
	  XEXP (rt_val, 1) = arg1;
	  va_end (p);
	  return rt_val;
	}

      hashcode = ((HOST_WIDE_INT) code + RTL_HASH (arg0) + RTL_HASH (arg1));
      for (h = attr_hash_table[hashcode % RTL_HASH_SIZE]; h; h = h->next)
	if (h->hashcode == hashcode
	    && GET_CODE (h->u.rtl) == code
	    && XEXP (h->u.rtl, 0) == arg0
	    && XEXP (h->u.rtl, 1) == arg1)
	  goto found;

      if (h == 0)
	{
	  rtl_obstack = hash_obstack;
	  rt_val = rtx_alloc (code);
	  XEXP (rt_val, 0) = arg0;
	  XEXP (rt_val, 1) = arg1;
	}
    }
  else if (GET_RTX_LENGTH (code) == 1
	   && GET_RTX_FORMAT (code)[0] == 's')
    {
      char * arg0 = va_arg (p, char *);

      if (code == SYMBOL_REF)
	arg0 = attr_string (arg0, strlen (arg0));

      hashcode = ((HOST_WIDE_INT) code + RTL_HASH (arg0));
      for (h = attr_hash_table[hashcode % RTL_HASH_SIZE]; h; h = h->next)
	if (h->hashcode == hashcode
	    && GET_CODE (h->u.rtl) == code
	    && XSTR (h->u.rtl, 0) == arg0)
	  goto found;

      if (h == 0)
	{
	  rtl_obstack = hash_obstack;
	  rt_val = rtx_alloc (code);
	  XSTR (rt_val, 0) = arg0;
	}
    }
  else if (GET_RTX_LENGTH (code) == 2
	   && GET_RTX_FORMAT (code)[0] == 's'
	   && GET_RTX_FORMAT (code)[1] == 's')
    {
      char *arg0 = va_arg (p, char *);
      char *arg1 = va_arg (p, char *);

      hashcode = ((HOST_WIDE_INT) code + RTL_HASH (arg0) + RTL_HASH (arg1));
      for (h = attr_hash_table[hashcode % RTL_HASH_SIZE]; h; h = h->next)
	if (h->hashcode == hashcode
	    && GET_CODE (h->u.rtl) == code
	    && XSTR (h->u.rtl, 0) == arg0
	    && XSTR (h->u.rtl, 1) == arg1)
	  goto found;

      if (h == 0)
	{
	  rtl_obstack = hash_obstack;
	  rt_val = rtx_alloc (code);
	  XSTR (rt_val, 0) = arg0;
	  XSTR (rt_val, 1) = arg1;
	}
    }
  else if (code == CONST_INT)
    {
      HOST_WIDE_INT arg0 = va_arg (p, HOST_WIDE_INT);
      if (arg0 == 0)
	return false_rtx;
      if (arg0 == 1)
	return true_rtx;
      goto nohash;
    }
  else
    {
    nohash:
      rt_val = rtx_alloc (code);	/* Allocate the storage space.  */
      
      fmt = GET_RTX_FORMAT (code);	/* Find the right format...  */
      for (i = 0; i < GET_RTX_LENGTH (code); i++)
	{
	  switch (*fmt++)
	    {
	    case '0':		/* Unused field.  */
	      break;

	    case 'i':		/* An integer?  */
	      XINT (rt_val, i) = va_arg (p, int);
	      break;

	    case 'w':		/* A wide integer? */
	      XWINT (rt_val, i) = va_arg (p, HOST_WIDE_INT);
	      break;

	    case 's':		/* A string?  */
	      XSTR (rt_val, i) = va_arg (p, char *);
	      break;

	    case 'e':		/* An expression?  */
	    case 'u':		/* An insn?  Same except when printing.  */
	      XEXP (rt_val, i) = va_arg (p, rtx);
	      break;

	    case 'E':		/* An RTX vector?  */
	      XVEC (rt_val, i) = va_arg (p, rtvec);
	      break;

	    default:
	      abort();
	    }
	}
      va_end (p);
      return rt_val;
    }

  rtl_obstack = old_obstack;
  va_end (p);
  attr_hash_add_rtx (hashcode, rt_val);
  RTX_INTEGRATED_P (rt_val) = 1;
  return rt_val;

 found:
  va_end (p);
  return h->u.rtl;
}

/* Create a new string printed with the printf line arguments into a space
   of at most LEN bytes:

   rtx attr_printf (len, format, [arg1, ..., argn])  */

#ifdef HAVE_VPRINTF

/*VARARGS2*/
static char *
attr_printf VPROTO((register int len, char *fmt, ...))
{
#ifndef __STDC__
  register int len;
  char *fmt;
#endif
  va_list p;
  register char *str;

  VA_START (p, fmt);

#ifndef __STDC__
  len = va_arg (p, int);
  fmt = va_arg (p, char*);
#endif

  /* Print the string into a temporary location.  */
  str = (char *) alloca (len);
  vsprintf (str, fmt, p);
  va_end (p);

  return attr_string (str, strlen (str));
}

#else /* not HAVE_VPRINTF */

static char *
attr_printf (len, fmt, arg1, arg2, arg3)
     int len;
     char *fmt;
     char *arg1, *arg2, *arg3; /* also int */
{
  register char *str;

  /* Print the string into a temporary location.  */
  str = (char *) alloca (len);
  sprintf (str, fmt, arg1, arg2, arg3);

  return attr_string (str, strlen (str));
}
#endif /* not HAVE_VPRINTF */

rtx
attr_eq (name, value)
     char *name, *value;
{
  return attr_rtx (EQ_ATTR, attr_string (name, strlen (name)),
		   attr_string (value, strlen (value)));
}

char *
attr_numeral (n)
     int n;
{
  return XSTR (make_numeric_value (n), 0);
}

/* Return a permanent (possibly shared) copy of a string STR (not assumed
   to be null terminated) with LEN bytes.  */

static char *
attr_string (str, len)
     char *str;
     int len;
{
  register struct attr_hash *h;
  int hashcode;
  int i;
  register char *new_str;

  /* Compute the hash code.  */
  hashcode = (len + 1) * 613 + (unsigned)str[0];
  for (i = 1; i <= len; i += 2)
    hashcode = ((hashcode * 613) + (unsigned)str[i]);
  if (hashcode < 0)
    hashcode = -hashcode;

  /* Search the table for the string.  */
  for (h = attr_hash_table[hashcode % RTL_HASH_SIZE]; h; h = h->next)
    if (h->hashcode == -hashcode && h->u.str[0] == str[0]
	&& !strncmp (h->u.str, str, len))
      return h->u.str;			/* <-- return if found.  */

  /* Not found; create a permanent copy and add it to the hash table.  */
  new_str = (char *) obstack_alloc (hash_obstack, len + 1);
  bcopy (str, new_str, len);
  new_str[len] = '\0';
  attr_hash_add_string (hashcode, new_str);

  return new_str;			/* Return the new string.  */
}

/* Check two rtx's for equality of contents,
   taking advantage of the fact that if both are hashed
   then they can't be equal unless they are the same object.  */

int
attr_equal_p (x, y)
     rtx x, y;
{
  return (x == y || (! (RTX_INTEGRATED_P (x) && RTX_INTEGRATED_P (y))
		     && rtx_equal_p (x, y)));
}

/* Copy an attribute value expression,
   descending to all depths, but not copying any
   permanent hashed subexpressions.  */

rtx
attr_copy_rtx (orig)
     register rtx orig;
{
  register rtx copy;
  register int i, j;