[deliverable/binutils-gdb.git] / mmalloc / mfree.c

/* Free a block of memory allocated by `mmalloc'.
   Copyright 1990, 1991, 1992 Free Software Foundation

   Written May 1989 by Mike Haertel.
   Heavily modified Mar 1992 by Fred Fish.  (fnf@cygnus.com)

The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.

The GNU C Library 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
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB.  If
not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.

   The author may be reached (Email) at the address mike@ai.mit.edu,
   or (US mail) as Mike Haertel c/o Free Software Foundation. */

#include "mmprivate.h"

/* Return memory to the heap.
   Like `mfree' but don't call a mfree_hook if there is one.  */

void
__mmalloc_free (mdp, ptr)
  struct mdesc *mdp;
  PTR ptr;
{
  int type;
  size_t block, blocks;
  register size_t i;
  struct list *prev, *next;

  block = BLOCK (ptr);

  type = mdp -> heapinfo[block].busy.type;
  switch (type)
    {
    case 0:
      /* Get as many statistics as early as we can.  */
      mdp -> heapstats.chunks_used--;
      mdp -> heapstats.bytes_used -=
	  mdp -> heapinfo[block].busy.info.size * BLOCKSIZE;
      mdp -> heapstats.bytes_free +=
	  mdp -> heapinfo[block].busy.info.size * BLOCKSIZE;

      /* Find the free cluster previous to this one in the free list.
	 Start searching at the last block referenced; this may benefit
	 programs with locality of allocation.  */
      i = mdp -> heapindex;
      if (i > block)
	{
	  while (i > block)
	    {
	      i = mdp -> heapinfo[i].free.prev;
	    }
	}
      else
	{
	  do
	    {
	      i = mdp -> heapinfo[i].free.next;
	    }
	  while ((i != 0) && (i < block));
	  i = mdp -> heapinfo[i].free.prev;
	}

      /* Determine how to link this block into the free list.  */
      if (block == i + mdp -> heapinfo[i].free.size)
	{
	  /* Coalesce this block with its predecessor.  */
	  mdp -> heapinfo[i].free.size +=
	    mdp -> heapinfo[block].busy.info.size;
	  block = i;
	}
      else
	{
	  /* Really link this block back into the free list.  */
	  mdp -> heapinfo[block].free.size =
	    mdp -> heapinfo[block].busy.info.size;
	  mdp -> heapinfo[block].free.next = mdp -> heapinfo[i].free.next;
	  mdp -> heapinfo[block].free.prev = i;
	  mdp -> heapinfo[i].free.next = block;
	  mdp -> heapinfo[mdp -> heapinfo[block].free.next].free.prev = block;
	  mdp -> heapstats.chunks_free++;
	}

      /* Now that the block is linked in, see if we can coalesce it
	 with its successor (by deleting its successor from the list
	 and adding in its size).  */
      if (block + mdp -> heapinfo[block].free.size ==
	  mdp -> heapinfo[block].free.next)
	{
	  mdp -> heapinfo[block].free.size
	    += mdp -> heapinfo[mdp -> heapinfo[block].free.next].free.size;
	  mdp -> heapinfo[block].free.next
	    = mdp -> heapinfo[mdp -> heapinfo[block].free.next].free.next;
	  mdp -> heapinfo[mdp -> heapinfo[block].free.next].free.prev = block;
	  mdp -> heapstats.chunks_free--;
	}

      /* Now see if we can return stuff to the system.  */
      blocks = mdp -> heapinfo[block].free.size;
      if (blocks >= FINAL_FREE_BLOCKS && block + blocks == mdp -> heaplimit
	  && mdp -> morecore (mdp, 0) == ADDRESS (block + blocks))
	{
	  register size_t bytes = blocks * BLOCKSIZE;
	  mdp -> heaplimit -= blocks;
	  mdp -> morecore (mdp, -bytes);
	  mdp -> heapinfo[mdp -> heapinfo[block].free.prev].free.next
	    = mdp -> heapinfo[block].free.next;
	  mdp -> heapinfo[mdp -> heapinfo[block].free.next].free.prev
	    = mdp -> heapinfo[block].free.prev;
	  block = mdp -> heapinfo[block].free.prev;
	  mdp -> heapstats.chunks_free--;
	  mdp -> heapstats.bytes_free -= bytes;
	}

      /* Set the next search to begin at this block.  */
      mdp -> heapindex = block;
      break;

    default:
      /* Do some of the statistics.  */
      mdp -> heapstats.chunks_used--;
      mdp -> heapstats.bytes_used -= 1 << type;
      mdp -> heapstats.chunks_free++;
      mdp -> heapstats.bytes_free += 1 << type;

      /* Get the address of the first free fragment in this block.  */
      prev = (struct list *)
	((char *) ADDRESS(block) +
	 (mdp -> heapinfo[block].busy.info.frag.first << type));

      if (mdp -> heapinfo[block].busy.info.frag.nfree ==
	  (BLOCKSIZE >> type) - 1)
	{
	  /* If all fragments of this block are free, remove them
	     from the fragment list and free the whole block.  */
	  next = prev;
	  for (i = 1; i < (size_t) (BLOCKSIZE >> type); ++i)
	    {
	      next = next -> next;
	    }
	  prev -> prev -> next = next;
	  if (next != NULL)
	    {
	      next -> prev = prev -> prev;
	    }
	  mdp -> heapinfo[block].busy.type = 0;
	  mdp -> heapinfo[block].busy.info.size = 1;

	  /* Keep the statistics accurate.  */
	  mdp -> heapstats.chunks_used++;
	  mdp -> heapstats.bytes_used += BLOCKSIZE;
	  mdp -> heapstats.chunks_free -= BLOCKSIZE >> type;
	  mdp -> heapstats.bytes_free -= BLOCKSIZE;

	  mfree ((PTR) mdp, (PTR) ADDRESS(block));
	}
      else if (mdp -> heapinfo[block].busy.info.frag.nfree != 0)
	{
	  /* If some fragments of this block are free, link this
	     fragment into the fragment list after the first free
	     fragment of this block. */
	  next = (struct list *) ptr;
	  next -> next = prev -> next;
	  next -> prev = prev;
	  prev -> next = next;
	  if (next -> next != NULL)
	    {
	      next -> next -> prev = next;
	    }
	  ++mdp -> heapinfo[block].busy.info.frag.nfree;
	}
      else
	{
	  /* No fragments of this block are free, so link this
	     fragment into the fragment list and announce that
	     it is the first free fragment of this block. */
	  prev = (struct list *) ptr;
	  mdp -> heapinfo[block].busy.info.frag.nfree = 1;
	  mdp -> heapinfo[block].busy.info.frag.first =
	    RESIDUAL (ptr, BLOCKSIZE) >> type;
	  prev -> next = mdp -> fraghead[type].next;
	  prev -> prev = &mdp -> fraghead[type];
	  prev -> prev -> next = prev;
	  if (prev -> next != NULL)
	    {
	      prev -> next -> prev = prev;
	    }
	}
      break;
    }
}

/* Return memory to the heap.  */

void
mfree (md, ptr)
  PTR md;
  PTR ptr;
{
  struct mdesc *mdp;
  register struct alignlist *l;

  if (ptr != NULL)
    {
      mdp = MD_TO_MDP (md);
      for (l = mdp -> aligned_blocks; l != NULL; l = l -> next)
	{
	  if (l -> aligned == ptr)
	    {
	      l -> aligned = NULL;  /* Mark the slot in the list as free. */
	      ptr = l -> exact;
	      break;
	    }
	}      
      if (mdp -> mfree_hook != NULL)
	{
	  (*mdp -> mfree_hook) (md, ptr);
	}
      else
	{
	  __mmalloc_free (mdp, ptr);
	}
    }
}

/* When using this package, provide a version of malloc/realloc/free built
   on top of it, so that if we use the default sbrk() region we will not
   collide with another malloc package trying to do the same thing, if
   the application contains any "hidden" calls to malloc/realloc/free (such
   as inside a system library). */

void
free (ptr)
  PTR ptr;
{
  mfree ((PTR) NULL, ptr);
}
Commit	Line	Data
c906108c SS	1	/* Free a block of memory allocated by `mmalloc'.
	2	Copyright 1990, 1991, 1992 Free Software Foundation
	3
	4	Written May 1989 by Mike Haertel.
	5	Heavily modified Mar 1992 by Fred Fish. (fnf@cygnus.com)
	6
	7	The GNU C Library is free software; you can redistribute it and/or
	8	modify it under the terms of the GNU Library General Public License as
	9	published by the Free Software Foundation; either version 2 of the
	10	License, or (at your option) any later version.
	11
	12	The GNU C Library is distributed in the hope that it will be useful,
	13	but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	15	Library General Public License for more details.
	16
	17	You should have received a copy of the GNU Library General Public
	18	License along with the GNU C Library; see the file COPYING.LIB. If
	19	not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
	20	Boston, MA 02111-1307, USA.
	21
	22	The author may be reached (Email) at the address mike@ai.mit.edu,
	23	or (US mail) as Mike Haertel c/o Free Software Foundation. */
	24
	25	#include "mmprivate.h"
	26
	27	/* Return memory to the heap.
	28	Like `mfree' but don't call a mfree_hook if there is one. */
	29
	30	void
	31	__mmalloc_free (mdp, ptr)
	32	struct mdesc *mdp;
	33	PTR ptr;
	34	{
	35	int type;
	36	size_t block, blocks;
	37	register size_t i;
	38	struct list prev, next;
	39
	40	block = BLOCK (ptr);
	41
	42	type = mdp -> heapinfo[block].busy.type;
	43	switch (type)
	44	{
	45	case 0:
	46	/* Get as many statistics as early as we can. */
	47	mdp -> heapstats.chunks_used--;
	48	mdp -> heapstats.bytes_used -=
	49	mdp -> heapinfo[block].busy.info.size * BLOCKSIZE;
	50	mdp -> heapstats.bytes_free +=
	51	mdp -> heapinfo[block].busy.info.size * BLOCKSIZE;
	52
	53	/* Find the free cluster previous to this one in the free list.
	54	Start searching at the last block referenced; this may benefit
	55	programs with locality of allocation. */
	56	i = mdp -> heapindex;
	57	if (i > block)
	58	{
	59	while (i > block)
	60	{
	61	i = mdp -> heapinfo[i].free.prev;
	62	}
	63	}
	64	else
65	{
66	do
67	{
68	i = mdp -> heapinfo[i].free.next;
69	}
70	while ((i != 0) && (i < block));
71	i = mdp -> heapinfo[i].free.prev;
72	}
73
74	/* Determine how to link this block into the free list. */
75	if (block == i + mdp -> heapinfo[i].free.size)
76	{
77	/* Coalesce this block with its predecessor. */
78	mdp -> heapinfo[i].free.size +=
79	mdp -> heapinfo[block].busy.info.size;
80	block = i;
81	}
82	else
83	{
84	/* Really link this block back into the free list. */
85	mdp -> heapinfo[block].free.size =
86	mdp -> heapinfo[block].busy.info.size;
87	mdp -> heapinfo[block].free.next = mdp -> heapinfo[i].free.next;
88	mdp -> heapinfo[block].free.prev = i;
89	mdp -> heapinfo[i].free.next = block;
90	mdp -> heapinfo[mdp -> heapinfo[block].free.next].free.prev = block;
91	mdp -> heapstats.chunks_free++;
92	}
93
94	/* Now that the block is linked in, see if we can coalesce it
95	with its successor (by deleting its successor from the list
96	and adding in its size). */
97	if (block + mdp -> heapinfo[block].free.size ==
98	mdp -> heapinfo[block].free.next)
99	{
100	mdp -> heapinfo[block].free.size
101	+= mdp -> heapinfo[mdp -> heapinfo[block].free.next].free.size;
102	mdp -> heapinfo[block].free.next
103	= mdp -> heapinfo[mdp -> heapinfo[block].free.next].free.next;
104	mdp -> heapinfo[mdp -> heapinfo[block].free.next].free.prev = block;
105	mdp -> heapstats.chunks_free--;
106	}
107
108	/* Now see if we can return stuff to the system. */
109	blocks = mdp -> heapinfo[block].free.size;
110	if (blocks >= FINAL_FREE_BLOCKS && block + blocks == mdp -> heaplimit
111	&& mdp -> morecore (mdp, 0) == ADDRESS (block + blocks))
112	{
113	register size_t bytes = blocks * BLOCKSIZE;
114	mdp -> heaplimit -= blocks;
115	mdp -> morecore (mdp, -bytes);
116	mdp -> heapinfo[mdp -> heapinfo[block].free.prev].free.next
117	= mdp -> heapinfo[block].free.next;
118	mdp -> heapinfo[mdp -> heapinfo[block].free.next].free.prev
119	= mdp -> heapinfo[block].free.prev;
120	block = mdp -> heapinfo[block].free.prev;
121	mdp -> heapstats.chunks_free--;
122	mdp -> heapstats.bytes_free -= bytes;
123	}
124
125	/* Set the next search to begin at this block. */
126	mdp -> heapindex = block;
127	break;
128
129	default:
130	/* Do some of the statistics. */
131	mdp -> heapstats.chunks_used--;
132	mdp -> heapstats.bytes_used -= 1 << type;
133	mdp -> heapstats.chunks_free++;
134	mdp -> heapstats.bytes_free += 1 << type;
135
136	/* Get the address of the first free fragment in this block. */
137	prev = (struct list *)
138	((char *) ADDRESS(block) +
139	(mdp -> heapinfo[block].busy.info.frag.first << type));
140
141	if (mdp -> heapinfo[block].busy.info.frag.nfree ==
142	(BLOCKSIZE >> type) - 1)
143	{
144	/* If all fragments of this block are free, remove them
145	from the fragment list and free the whole block. */
146	next = prev;
147	for (i = 1; i < (size_t) (BLOCKSIZE >> type); ++i)
148	{
149	next = next -> next;
150	}
151	prev -> prev -> next = next;
152	if (next != NULL)
153	{
154	next -> prev = prev -> prev;
155	}
156	mdp -> heapinfo[block].busy.type = 0;
157	mdp -> heapinfo[block].busy.info.size = 1;
158
159	/* Keep the statistics accurate. */
160	mdp -> heapstats.chunks_used++;
161	mdp -> heapstats.bytes_used += BLOCKSIZE;
162	mdp -> heapstats.chunks_free -= BLOCKSIZE >> type;
163	mdp -> heapstats.bytes_free -= BLOCKSIZE;
164
165	mfree ((PTR) mdp, (PTR) ADDRESS(block));
166	}
167	else if (mdp -> heapinfo[block].busy.info.frag.nfree != 0)
168	{
169	/* If some fragments of this block are free, link this
170	fragment into the fragment list after the first free
171	fragment of this block. */
172	next = (struct list *) ptr;
173	next -> next = prev -> next;
174	next -> prev = prev;
175	prev -> next = next;
176	if (next -> next != NULL)
177	{
178	next -> next -> prev = next;
179	}
180	++mdp -> heapinfo[block].busy.info.frag.nfree;
181	}
182	else
183	{
184	/* No fragments of this block are free, so link this
185	fragment into the fragment list and announce that
186	it is the first free fragment of this block. */
187	prev = (struct list *) ptr;
188	mdp -> heapinfo[block].busy.info.frag.nfree = 1;
189	mdp -> heapinfo[block].busy.info.frag.first =
190	RESIDUAL (ptr, BLOCKSIZE) >> type;
191	prev -> next = mdp -> fraghead[type].next;
192	prev -> prev = &mdp -> fraghead[type];
193	prev -> prev -> next = prev;
194	if (prev -> next != NULL)
195	{
196	prev -> next -> prev = prev;
197	}
198	}
199	break;
200	}
201	}
202
203	/* Return memory to the heap. */
204
205	void
206	mfree (md, ptr)
207	PTR md;
208	PTR ptr;
209	{
210	struct mdesc *mdp;
211	register struct alignlist *l;
212
213	if (ptr != NULL)
214	{
215	mdp = MD_TO_MDP (md);
216	for (l = mdp -> aligned_blocks; l != NULL; l = l -> next)
217	{
218	if (l -> aligned == ptr)
219	{
220	l -> aligned = NULL; /* Mark the slot in the list as free. */
221	ptr = l -> exact;
222	break;
223	}
224	}
225	if (mdp -> mfree_hook != NULL)
226	{
227	(*mdp -> mfree_hook) (md, ptr);
228	}
229	else
230	{
231	__mmalloc_free (mdp, ptr);
232	}
233	}
234	}
235
236	/* When using this package, provide a version of malloc/realloc/free built
237	on top of it, so that if we use the default sbrk() region we will not
238	collide with another malloc package trying to do the same thing, if
239	the application contains any "hidden" calls to malloc/realloc/free (such
240	as inside a system library). */
241
242	void
243	free (ptr)
244	PTR ptr;
245	{
246	mfree ((PTR) NULL, ptr);
247	}