rtl.c

早期freebsd实现

dump_and_abort (expected_c, actual_c, infile)
     int expected_c, actual_c;
     FILE *infile;
{
  int c, i;

  if (expected_c >= 0)
    fprintf (stderr,
	     "Expected character %c.  Found character %c.",
	     expected_c, actual_c);
  fprintf (stderr, "  At file position: %ld\n", ftell (infile));
  fprintf (stderr, "Following characters are:\n\t");
  for (i = 0; i < 200; i++)
    {
      c = getc (infile);
      if (EOF == c) break;
      putc (c, stderr);
    }
  fprintf (stderr, "Aborting.\n");
  abort ();
}

/* Read chars from INFILE until a non-whitespace char
   and return that.  Comments, both Lisp style and C style,
   are treated as whitespace.
   Tools such as genflags use this function.  */

int
read_skip_spaces (infile)
     FILE *infile;
{
  register int c;
  while (c = getc (infile))
    {
      if (c == ' ' || c == '\n' || c == '\t' || c == '\f')
	;
      else if (c == ';')
	{
	  while ((c = getc (infile)) && c != '\n') ;
	}
      else if (c == '/')
	{
	  register int prevc;
	  c = getc (infile);
	  if (c != '*')
	    dump_and_abort ('*', c, infile);
	  
	  prevc = 0;
	  while (c = getc (infile))
	    {
	      if (prevc == '*' && c == '/')
		break;
	      prevc = c;
	    }
	}
      else break;
    }
  return c;
}

/* Read an rtx code name into the buffer STR[].
   It is terminated by any of the punctuation chars of rtx printed syntax.  */

static void
read_name (str, infile)
     char *str;
     FILE *infile;
{
  register char *p;
  register int c;

  c = read_skip_spaces(infile);

  p = str;
  while (1)
    {
      if (c == ' ' || c == '\n' || c == '\t' || c == '\f')
	break;
      if (c == ':' || c == ')' || c == ']' || c == '"' || c == '/'
	  || c == '(' || c == '[')
	{
	  ungetc (c, infile);
	  break;
	}
      *p++ = c;
      c = getc (infile);
    }
  if (p == str)
    {
      fprintf (stderr, "missing name or number");
      dump_and_abort (-1, -1, infile);
    }

  *p = 0;
}

/* Read an rtx in printed representation from INFILE
   and return an actual rtx in core constructed accordingly.
   read_rtx is not used in the compiler proper, but rather in
   the utilities gen*.c that construct C code from machine descriptions.  */

rtx
read_rtx (infile)
     FILE *infile;
{
  register int i, j, list_counter;
  RTX_CODE tmp_code;
  register char *format_ptr;
  /* tmp_char is a buffer used for reading decimal integers
     and names of rtx types and machine modes.
     Therefore, 256 must be enough.  */
  char tmp_char[256];
  rtx return_rtx;
  register int c;
  int tmp_int;
  HOST_WIDE_INT tmp_wide;

  /* Linked list structure for making RTXs: */
  struct rtx_list
    {
      struct rtx_list *next;
      rtx value;		/* Value of this node...		*/
    };

  c = read_skip_spaces (infile); /* Should be open paren.  */
  if (c != '(')
    dump_and_abort ('(', c, infile);

  read_name (tmp_char, infile);

  tmp_code = UNKNOWN;

  for (i=0; i < NUM_RTX_CODE; i++) /* @@ might speed this search up */
    {
      if (!(strcmp (tmp_char, GET_RTX_NAME (i))))
	{
	  tmp_code = (RTX_CODE) i;	/* get value for name */
	  break;
	}
    }
  if (tmp_code == UNKNOWN)
    {
      fprintf (stderr,
	       "Unknown rtx read in rtl.read_rtx(). Code name was %s .",
	       tmp_char);
    }
  /* (NIL) stands for an expression that isn't there.  */
  if (tmp_code == NIL)
    {
      /* Discard the closeparen.  */
      while ((c = getc (infile)) && c != ')');
      return 0;
    }

  return_rtx = rtx_alloc (tmp_code); /* if we end up with an insn expression
				       then we free this space below.  */
  format_ptr = GET_RTX_FORMAT (GET_CODE (return_rtx));

  /* If what follows is `: mode ', read it and
     store the mode in the rtx.  */

  i = read_skip_spaces (infile);
  if (i == ':')
    {
      register int k;
      read_name (tmp_char, infile);
      for (k = 0; k < NUM_MACHINE_MODES; k++)
	if (!strcmp (GET_MODE_NAME (k), tmp_char))
	  break;

      PUT_MODE (return_rtx, (enum machine_mode) k );
    }
  else
    ungetc (i, infile);

  for (i = 0; i < GET_RTX_LENGTH (GET_CODE (return_rtx)); i++)
    switch (*format_ptr++)
      {
	/* 0 means a field for internal use only.
	   Don't expect it to be present in the input.  */
      case '0':
	break;

      case 'e':
      case 'u':
	XEXP (return_rtx, i) = read_rtx (infile);
	break;

      case 'V':
	/* 'V' is an optional vector: if a closeparen follows,
	   just store NULL for this element.  */
	c = read_skip_spaces (infile);
	ungetc (c, infile);
	if (c == ')')
	  {
	    XVEC (return_rtx, i) = 0;
	    break;
 	  }
	/* Now process the vector.  */
  
      case 'E':
	{
	  register struct rtx_list *next_rtx, *rtx_list_link;
	  struct rtx_list *list_rtx;

	  c = read_skip_spaces (infile);
	  if (c != '[')
	    dump_and_abort ('[', c, infile);

	  /* add expressions to a list, while keeping a count */
	  next_rtx = NULL;
	  list_counter = 0;
	  while ((c = read_skip_spaces (infile)) && c != ']')
	    {
	      ungetc (c, infile);
	      list_counter++;
	      rtx_list_link = (struct rtx_list *)
		alloca (sizeof (struct rtx_list));
	      rtx_list_link->value = read_rtx (infile);
	      if (next_rtx == 0)
		list_rtx = rtx_list_link;
	      else
		next_rtx->next = rtx_list_link;
	      next_rtx = rtx_list_link;
	      rtx_list_link->next = 0;
	    }
	  /* get vector length and allocate it */
	  XVEC (return_rtx, i) = (list_counter
				  ? rtvec_alloc (list_counter) : NULL_RTVEC);
	  if (list_counter > 0)
	    {
	      next_rtx = list_rtx;
	      for (j = 0; j < list_counter; j++,
		   next_rtx = next_rtx->next)
		XVECEXP (return_rtx, i, j) = next_rtx->value;
	    }
	  /* close bracket gotten */
	}
	break;

      case 'S':
	/* 'S' is an optional string: if a closeparen follows,
	   just store NULL for this element.  */
	c = read_skip_spaces (infile);
	ungetc (c, infile);
	if (c == ')')
	  {
	    XSTR (return_rtx, i) = 0;
	    break;
	  }

      case 's':
	{
	  int saw_paren = 0;
	  register char *stringbuf;
	  int stringbufsize;

	  c = read_skip_spaces (infile);
	  if (c == '(')
	    {
	      saw_paren = 1;
	      c = read_skip_spaces (infile);
	    }
	  if (c != '"')
	    dump_and_abort ('"', c, infile);

	  while (1)
	    {
	      c = getc (infile); /* Read the string  */
	      if (c == '\\')
		{
		  c = getc (infile);	/* Read the string  */
		  /* \; makes stuff for a C string constant containing
		     newline and tab.  */
		  if (c == ';')
		    {
		      obstack_grow (rtl_obstack, "\\n\\t", 4);
		      continue;
		    }
		}
	      else if (c == '"')
		break;

	      obstack_1grow (rtl_obstack, c);
	    }

	  obstack_1grow (rtl_obstack, 0);
	  stringbuf = (char *) obstack_finish (rtl_obstack);

	  if (saw_paren)
	    {
	      c = read_skip_spaces (infile);
	      if (c != ')')
		dump_and_abort (')', c, infile);
	    }
	  XSTR (return_rtx, i) = stringbuf;
	}
	break;

      case 'w':
	read_name (tmp_char, infile);
#if HOST_BITS_PER_WIDE_INT == HOST_BITS_PER_INT
	tmp_wide = atoi (tmp_char);
#else
	tmp_wide = atol (tmp_char);
#endif
	XWINT (return_rtx, i) = tmp_wide;
	break;

      case 'i':
      case 'n':
	read_name (tmp_char, infile);
	tmp_int = atoi (tmp_char);
	XINT (return_rtx, i) = tmp_int;
	break;

      default:
	fprintf (stderr,
		 "switch format wrong in rtl.read_rtx(). format was: %c.\n",
		 format_ptr[-1]);
	fprintf (stderr, "\tfile position: %ld\n", ftell (infile));
	abort ();
      }

  c = read_skip_spaces (infile);
  if (c != ')')
    dump_and_abort (')', c, infile);

  return return_rtx;
}

/* This is called once per compilation, before any rtx's are constructed.
   It initializes the vector `rtx_length', the extra CC modes, if any,
   and computes certain commonly-used modes.  */

void
init_rtl ()
{
  int min_class_size[(int) MAX_MODE_CLASS];
  enum machine_mode mode;
  int i;

  for (i = 0; i < NUM_RTX_CODE; i++)
    rtx_length[i] = strlen (rtx_format[i]);

  /* Make CONST_DOUBLE bigger, if real values are bigger than
     it normally expects to have room for.
     Note that REAL_VALUE_TYPE is not defined by default,
     since tree.h is not included.  But the default dfn as `double'
     would do no harm.  */
#ifdef REAL_VALUE_TYPE
  i = sizeof (REAL_VALUE_TYPE) / sizeof (rtunion) + 2;
  if (rtx_length[(int) CONST_DOUBLE] < i)
    {
      char *s = (char *) xmalloc (i + 1);
      rtx_length[(int) CONST_DOUBLE] = i;
      rtx_format[(int) CONST_DOUBLE] = s;
      *s++ = 'e';
      *s++ = '0';
      /* Set the GET_RTX_FORMAT of CONST_DOUBLE to a string
	 of as many `i's as we now have elements.  */
      for (i = 0; i < rtx_length[(int) CONST_DOUBLE]; i++)
	*s++ = 'w';
      *s++ = 0;
    }
#endif

#ifdef EXTRA_CC_MODES
  for (i = (int) CCmode + 1; i < (int) MAX_MACHINE_MODE; i++)
    {
      mode_class[i] = MODE_CC;
      mode_size[i] = mode_size[(int) CCmode];
      mode_unit_size[i] = mode_unit_size[(int) CCmode];
      mode_wider_mode[i - 1] = (enum machine_mode) i;
      mode_wider_mode[i] = VOIDmode;
    }
#endif

  /* Find the narrowest mode for each class and compute the word and byte
     modes.  */

  for (i = 0; i < (int) MAX_MODE_CLASS; i++)
    min_class_size[i] = 1000;

  byte_mode = VOIDmode;
  word_mode = VOIDmode;

  for (mode = VOIDmode; (int) mode < (int) MAX_MACHINE_MODE;
       mode = (enum machine_mode) ((int) mode + 1))
    {
      if (GET_MODE_SIZE (mode) < min_class_size[(int) GET_MODE_CLASS (mode)])
	{
	  class_narrowest_mode[(int) GET_MODE_CLASS (mode)] = mode;
	  min_class_size[(int) GET_MODE_CLASS (mode)] = GET_MODE_SIZE (mode);
	}
      if (GET_MODE_CLASS (mode) == MODE_INT
	  && GET_MODE_BITSIZE (mode) == BITS_PER_UNIT
	  && byte_mode == VOIDmode)
	byte_mode = mode;

      if (GET_MODE_CLASS (mode) == MODE_INT
	  && GET_MODE_BITSIZE (mode) == BITS_PER_WORD
	  && word_mode == VOIDmode)
	word_mode = mode;
    }
}

#ifdef memset
gcc_memset (dest, value, len)
     char *dest;
     int value;
     int len;
{
  while (len-- > 0)
    *dest++ = value;
}
#endif /* memset */