/* Functions to support general ended bitmaps.
   Copyright (C) 1997 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.  */

/* Number of words to use for each element in the linked list.  */

#ifndef BITMAP_ELEMENT_WORDS
#define BITMAP_ELEMENT_WORDS 2
#endif

/* Number of bits in each actual element of a bitmap.  We get slightly better
   code for bit % BITMAP_ELEMENT_ALL_BITS and bit / BITMAP_ELEMENT_ALL_BITS if
   bits is unsigned, assuming it is a power of 2.  */

#define BITMAP_ELEMENT_ALL_BITS \
  ((unsigned) (BITMAP_ELEMENT_WORDS * HOST_BITS_PER_WIDE_INT))

/* Bitmap set element.  We use a linked list to hold only the bits that
   are set.  This allows for use to grow the bitset dynamically without
   having to realloc and copy a giant bit array.  The `prev' field is
   undefined for an element on the free list.  */

typedef struct bitmap_element_def
{
  struct bitmap_element_def *next;		/* Next element. */
  struct bitmap_element_def *prev;		/* Previous element. */
  unsigned int indx;			/* regno/BITMAP_ELEMENT_ALL_BITS. */
  unsigned HOST_WIDE_INT bits[BITMAP_ELEMENT_WORDS]; /* Bits that are set. */
} bitmap_element;

/* Head of bitmap linked list.  */
typedef struct bitmap_head_def {
  bitmap_element *first;	/* First element in linked list. */
  bitmap_element *current;	/* Last element looked at. */
  int indx;			/* Index of last element looked at. */
} bitmap_head, *bitmap;

/* Enumeration giving the various operations we support.  */
enum bitmap_bits {
  BITMAP_AND,			/* TO = FROM1 & FROM2 */
  BITMAP_AND_COMPL,		/* TO = FROM1 & ~ FROM2 */
  BITMAP_IOR			/* TO = FROM1 | FROM2 */
};

/* Global data */
extern bitmap_element *bitmap_free;	/* Freelist of bitmap elements */
extern bitmap_element bitmap_zero;	/* Zero bitmap element */

/* Clear a bitmap by freeing up the linked list.  */
extern void bitmap_clear PROTO((bitmap));

/* Copy a bitmap to another bitmap. */
extern void bitmap_copy PROTO((bitmap, bitmap));

/* Perform an operation on two bitmaps, yielding a third.  */
extern void bitmap_operation PROTO((bitmap, bitmap, bitmap, enum bitmap_bits));

/* `or' into one bitmap the `and' of a second bitmap witih the complement
   of a third.  */
extern void bitmap_ior_and_compl PROTO((bitmap, bitmap, bitmap));

/* Clear a single register in a register set.  */
extern void bitmap_clear_bit PROTO((bitmap, int));

/* Set a single register in a register set.  */
extern void bitmap_set_bit PROTO((bitmap, int));

/* Return true if a register is set in a register set.  */
extern int bitmap_bit_p PROTO((bitmap, int));

/* Debug functions to print a bitmap linked list.  */
extern void bitmap_debug PROTO((bitmap));
extern void bitmap_debug_file STDIO_PROTO((FILE *, bitmap));

/* Initialize a bitmap header.  */
extern bitmap bitmap_initialize PROTO((bitmap));

/* Release all memory held by bitmaps.  */
extern void bitmap_release_memory PROTO((void));

/* Allocate a bitmap with oballoc.  */
#define BITMAP_OBSTACK_ALLOC(OBSTACK)				\
  bitmap_initialize ((bitmap) obstack_alloc (OBSTACK, sizeof (bitmap_head)))

/* Allocate a bitmap with alloca.  */
#define BITMAP_ALLOCA()						\
  bitmap_initialize ((bitmap) alloca (sizeof (bitmap_head)))

/* Do any cleanup needed on a bitmap when it is no longer used.  */
#define BITMAP_FREE(BITMAP)					\
do {				\
  if (BITMAP)			\
    {				\
      bitmap_clear (BITMAP);	\
      (BITMAP) = 0;		\
    }									\
} while (0)

/* Do any one-time initializations needed for bitmaps.  */
#define BITMAP_INIT_ONCE()

/* Loop over all bits in BITMAP, starting with MIN, setting BITNUM to the
   bit number and executing CODE for all bits that are set. */

#define EXECUTE_IF_SET_IN_BITMAP(BITMAP, MIN, BITNUM, CODE)		\
do {									\
  bitmap_element *ptr_ = (BITMAP)->first;				\
  unsigned int indx_ = (MIN) / BITMAP_ELEMENT_ALL_BITS;			\
  unsigned bit_num_ = (MIN) % ((unsigned) HOST_BITS_PER_WIDE_INT);	\
  unsigned word_num_ = (((MIN) / ((unsigned) HOST_BITS_PER_WIDE_INT))	\
			% BITMAP_ELEMENT_WORDS);			\
									\
									\
  /* Find the block the minimum bit is in.  */				\
  while (ptr_ != 0 && ptr_->indx < indx_)				\
    ptr_ = ptr_->next;							\
									\
  if (ptr_ != 0 && ptr_->indx != indx_)					\
    {									\
      bit_num_ = 0;							\
      word_num_ = 0;							\
    }									\
									\
  for (; ptr_ != 0; ptr_ = ptr_->next)					\
    {									\
      for (; word_num_ < BITMAP_ELEMENT_WORDS; word_num_++)		\
	{								\
	  unsigned HOST_WIDE_INT word_ = ptr_->bits[word_num_];		\
									\
	  if (word_ != 0)						\
	    {								\
	      for (; bit_num_ < HOST_BITS_PER_WIDE_INT; bit_num_++)	\
		{							\
		  unsigned HOST_WIDE_INT mask_				\
		    = ((unsigned HOST_WIDE_INT) 1) << bit_num_;		\
									\
		  if ((word_ & mask_) != 0)				\
		    {							\
		      word_ &= ~ mask_;					\
		      (BITNUM) = (ptr_->indx * BITMAP_ELEMENT_ALL_BITS  \
				  + word_num_ * HOST_BITS_PER_WIDE_INT  \
				  + bit_num_);				\
		      CODE;						\
									\
		      if (word_ == 0)					\
			break;						\
		    }							\
		}							\
	    }								\
									\
	  bit_num_ = 0;							\
	}								\
									\
      word_num_ = 0;							\
    }									\
} while (0)

/* Loop over all bits in BITMAP1 and BITMAP2, starting with MIN, setting
   BITNUM to the bit number and executing CODE for all bits that are set in
   the first bitmap and not set in the second. */

#define EXECUTE_IF_AND_COMPL_IN_BITMAP(BITMAP1, BITMAP2, MIN, BITNUM, CODE) \
do {									\
  bitmap_element *ptr1_ = (BITMAP1)->first;				\
  bitmap_element *ptr2_ = (BITMAP2)->first;				\
  unsigned int indx_ = (MIN) / BITMAP_ELEMENT_ALL_BITS;			\
  unsigned bit_num_ = (MIN) % ((unsigned) HOST_BITS_PER_WIDE_INT);	\
  unsigned word_num_ = (((MIN) / ((unsigned) HOST_BITS_PER_WIDE_INT))	\
			% BITMAP_ELEMENT_WORDS);			\
									\
  /* Find the block the minimum bit is in in the first bitmap.  */	\
  while (ptr1_ != 0 && ptr1_->indx < indx_)				\
    ptr1_ = ptr1_->next;						\
									\
  if (ptr1_ != 0 && ptr1_->indx != indx_)				\
    {									\
      bit_num_ = 0;							\
      word_num_ = 0;							\
    }									\
									\
  for (; ptr1_ != 0 ; ptr1_ = ptr1_->next)				\
    {									\
      /* Advance BITMAP2 to the equivalent link, using an all		\
	 zero element if an equavialent link doesn't exist.  */		\
      bitmap_element *tmp2_;						\
									\
      while (ptr2_ != 0 && ptr2_->indx < ptr1_->indx)			\
	ptr2_ = ptr2_->next;						\
									\
      tmp2_ = ((ptr2_ != 0 && ptr2_->indx == ptr1_->indx)		\
	       ? ptr2_ : &bitmap_zero); 				\
									\
      for (; word_num_ < BITMAP_ELEMENT_WORDS; word_num_++)		\
	{								\
	  unsigned HOST_WIDE_INT word_ = (ptr1_->bits[word_num_]	\
					  & ~ tmp2_->bits[word_num_]);	\
	  if (word_ != 0)						\
	    {								\
	      for (; bit_num_ < HOST_BITS_PER_WIDE_INT; bit_num_++)	\
		{							\
		  unsigned HOST_WIDE_INT mask_				\
		    = ((unsigned HOST_WIDE_INT)1) << bit_num_;		\
									\
		  if ((word_ & mask_) != 0)				\
		    {							\
		      word_ &= ~ mask_;					\
		      (BITNUM) = (ptr1_->indx * BITMAP_ELEMENT_ALL_BITS \
				  + word_num_ * HOST_BITS_PER_WIDE_INT  \
				  + bit_num_);				\
									\
		      CODE;						\
		      if (word_ == 0)					\
			break;						\
		    }							\
		}							\
	    }								\
									\
	  bit_num_ = 0;							\
	}								\
									\
      word_num_ = 0;							\
    }									\
} while (0)
