mallocx.c

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/*
 * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
 * Copyright (c) 1991-1994 by Xerox Corporation.  All rights reserved.
 * Copyright (c) 1996 by Silicon Graphics.  All rights reserved.
 * Copyright (c) 2000 by Hewlett-Packard Company.  All rights reserved.
 *
 * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
 * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
 *
 * Permission is hereby granted to use or copy this program
 * for any purpose,  provided the above notices are retained on all copies.
 * Permission to modify the code and to distribute modified code is granted,
 * provided the above notices are retained, and a notice that the code was
 * modified is included with the above copyright notice.
 */

/*
 * These are extra allocation routines which are likely to be less
 * frequently used than those in malloc.c.  They are separate in the
 * hope that the .o file will be excluded from statically linked
 * executables.  We should probably break this up further.
 */

#include <stdio.h>
#include "private/gc_priv.h"

extern ptr_t GC_clear_stack();  /* in misc.c, behaves like identity */
void GC_extend_size_map();      /* in misc.c. */
GC_bool GC_alloc_reclaim_list();	/* in malloc.c */

/* Some externally visible but unadvertised variables to allow access to */
/* free lists from inlined allocators without including gc_priv.h	 */
/* or introducing dependencies on internal data structure layouts.	 */
ptr_t * GC_CONST GC_objfreelist_ptr = GC_objfreelist;
ptr_t * GC_CONST GC_aobjfreelist_ptr = GC_aobjfreelist;
ptr_t * GC_CONST GC_uobjfreelist_ptr = GC_uobjfreelist;
# ifdef ATOMIC_UNCOLLECTABLE
    ptr_t * GC_CONST GC_auobjfreelist_ptr = GC_auobjfreelist;
# endif


GC_PTR GC_generic_or_special_malloc(lb,knd)
word lb;
int knd;
{
    switch(knd) {
#     ifdef STUBBORN_ALLOC
	case STUBBORN:
	    return(GC_malloc_stubborn((size_t)lb));
#     endif
	case PTRFREE:
	    return(GC_malloc_atomic((size_t)lb));
	case NORMAL:
	    return(GC_malloc((size_t)lb));
	case UNCOLLECTABLE:
	    return(GC_malloc_uncollectable((size_t)lb));
#       ifdef ATOMIC_UNCOLLECTABLE
	  case AUNCOLLECTABLE:
	    return(GC_malloc_atomic_uncollectable((size_t)lb));
#	endif /* ATOMIC_UNCOLLECTABLE */
	default:
	    return(GC_generic_malloc(lb,knd));
    }
}


/* Change the size of the block pointed to by p to contain at least   */
/* lb bytes.  The object may be (and quite likely will be) moved.     */
/* The kind (e.g. atomic) is the same as that of the old.	      */
/* Shrinking of large blocks is not implemented well.                 */
# ifdef __STDC__
    GC_PTR GC_realloc(GC_PTR p, size_t lb)
# else
    GC_PTR GC_realloc(p,lb)
    GC_PTR p;
    size_t lb;
# endif
{
register struct hblk * h;
register hdr * hhdr;
register word sz;	 /* Current size in bytes	*/
register word orig_sz;	 /* Original sz in bytes	*/
int obj_kind;

    if (p == 0) return(GC_malloc(lb));	/* Required by ANSI */
    h = HBLKPTR(p);
    hhdr = HDR(h);
    sz = hhdr -> hb_sz;
    obj_kind = hhdr -> hb_obj_kind;
    sz = WORDS_TO_BYTES(sz);
    orig_sz = sz;

    if (sz > MAXOBJBYTES) {
	/* Round it up to the next whole heap block */
	  register word descr;
	  
	  sz = (sz+HBLKSIZE-1) & (~HBLKMASK);
	  hhdr -> hb_sz = BYTES_TO_WORDS(sz);
	  descr = GC_obj_kinds[obj_kind].ok_descriptor;
          if (GC_obj_kinds[obj_kind].ok_relocate_descr) descr += sz;
          hhdr -> hb_descr = descr;
	  if (IS_UNCOLLECTABLE(obj_kind)) GC_non_gc_bytes += (sz - orig_sz);
	  /* Extra area is already cleared by GC_alloc_large_and_clear. */
    }
    if (ADD_SLOP(lb) <= sz) {
	if (lb >= (sz >> 1)) {
#	    ifdef STUBBORN_ALLOC
	        if (obj_kind == STUBBORN) GC_change_stubborn(p);
#	    endif
	    if (orig_sz > lb) {
	      /* Clear unneeded part of object to avoid bogus pointer */
	      /* tracing.					      */
	      /* Safe for stubborn objects.			      */
	        BZERO(((ptr_t)p) + lb, orig_sz - lb);
	    }
	    return(p);
	} else {
	    /* shrink */
	      GC_PTR result =
	      		GC_generic_or_special_malloc((word)lb, obj_kind);

	      if (result == 0) return(0);
	          /* Could also return original object.  But this 	*/
	          /* gives the client warning of imminent disaster.	*/
	      BCOPY(p, result, lb);
#	      ifndef IGNORE_FREE
	        GC_free(p);
#	      endif
	      return(result);
	}
    } else {
	/* grow */
	  GC_PTR result =
	  	GC_generic_or_special_malloc((word)lb, obj_kind);

	  if (result == 0) return(0);
	  BCOPY(p, result, sz);
#	  ifndef IGNORE_FREE
	    GC_free(p);
#	  endif
	  return(result);
    }
}

# if defined(REDIRECT_MALLOC) && !defined(REDIRECT_REALLOC)
#   define REDIRECT_REALLOC GC_realloc
# endif

# ifdef REDIRECT_REALLOC

/* As with malloc, avoid two levels of extra calls here.	*/
# ifdef GC_ADD_CALLER
#   define RA GC_RETURN_ADDR,
# else
#   define RA
# endif
# define GC_debug_realloc_replacement(p, lb) \
	GC_debug_realloc(p, lb, RA "unknown", 0)

# ifdef __STDC__
    GC_PTR realloc(GC_PTR p, size_t lb)
# else
    GC_PTR realloc(p,lb)
    GC_PTR p;
    size_t lb;
# endif
  {
    return(REDIRECT_REALLOC(p, lb));
  }

# undef GC_debug_realloc_replacement
# endif /* REDIRECT_REALLOC */


/* Allocate memory such that only pointers to near the 		*/
/* beginning of the object are considered.			*/
/* We avoid holding allocation lock while we clear memory.	*/
ptr_t GC_generic_malloc_ignore_off_page(lb, k)
register size_t lb;
register int k;
{
    register ptr_t result;
    word lw;
    word n_blocks;
    GC_bool init;
    DCL_LOCK_STATE;
    
    if (SMALL_OBJ(lb))
        return(GC_generic_malloc((word)lb, k));
    lw = ROUNDED_UP_WORDS(lb);
    n_blocks = OBJ_SZ_TO_BLOCKS(lw);
    init = GC_obj_kinds[k].ok_init;
    if (GC_have_errors) GC_print_all_errors();
    GC_INVOKE_FINALIZERS();
    DISABLE_SIGNALS();
    LOCK();
    result = (ptr_t)GC_alloc_large(lw, k, IGNORE_OFF_PAGE);
    if (0 != result) {
        if (GC_debugging_started) {
	    BZERO(result, n_blocks * HBLKSIZE);
        } else {
#           ifdef THREADS
	      /* Clear any memory that might be used for GC descriptors */
	      /* before we release the lock.			      */
	        ((word *)result)[0] = 0;
	        ((word *)result)[1] = 0;
	        ((word *)result)[lw-1] = 0;
	        ((word *)result)[lw-2] = 0;
#	    endif
        }
    }
    GC_words_allocd += lw;
    UNLOCK();
    ENABLE_SIGNALS();
    if (0 == result) {
        return((*GC_oom_fn)(lb));
    } else {
    	if (init && !GC_debugging_started) {
	    BZERO(result, n_blocks * HBLKSIZE);
        }
        return(result);
    }
}

# if defined(__STDC__) || defined(__cplusplus)
  void * GC_malloc_ignore_off_page(size_t lb)
# else
  char * GC_malloc_ignore_off_page(lb)
  register size_t lb;
# endif
{
    return((GC_PTR)GC_generic_malloc_ignore_off_page(lb, NORMAL));
}

# if defined(__STDC__) || defined(__cplusplus)
  void * GC_malloc_atomic_ignore_off_page(size_t lb)
# else
  char * GC_malloc_atomic_ignore_off_page(lb)
  register size_t lb;
# endif
{
    return((GC_PTR)GC_generic_malloc_ignore_off_page(lb, PTRFREE));
}

/* Increment GC_words_allocd from code that doesn't have direct access 	*/
/* to GC_arrays.							*/
# ifdef __STDC__
void GC_incr_words_allocd(size_t n)
{
    GC_words_allocd += n;
}

/* The same for GC_mem_freed.				*/
void GC_incr_mem_freed(size_t n)
{
    GC_mem_freed += n;
}
# endif /* __STDC__ */

/* Analogous to the above, but assumes a small object size, and 	*/
/* bypasses MERGE_SIZES mechanism.  Used by gc_inline.h.		*/
ptr_t GC_generic_malloc_words_small_inner(lw, k)
register word lw;
register int k;
{
register ptr_t op;
register ptr_t *opp;
register struct obj_kind * kind = GC_obj_kinds + k;

    opp = &(kind -> ok_freelist[lw]);
    if( (op = *opp) == 0 ) {
        if (!GC_is_initialized) {
            GC_init_inner();
        }
	if (kind -> ok_reclaim_list != 0 || GC_alloc_reclaim_list(kind)) {
	    op = GC_clear_stack(GC_allocobj((word)lw, k));
	}
	if (op == 0) {
	    UNLOCK();
	    ENABLE_SIGNALS();
	    return ((*GC_oom_fn)(WORDS_TO_BYTES(lw)));
	}
    }
    *opp = obj_link(op);
    obj_link(op) = 0;
    GC_words_allocd += lw;
    return((ptr_t)op);
}

/* Analogous to the above, but assumes a small object size, and 	*/
/* bypasses MERGE_SIZES mechanism.  Used by gc_inline.h.		*/
#ifdef __STDC__
     ptr_t GC_generic_malloc_words_small(size_t lw, int k)
#else 
     ptr_t GC_generic_malloc_words_small(lw, k)
     register word lw;
     register int k;
#endif
{
register ptr_t op;
DCL_LOCK_STATE;

    if (GC_have_errors) GC_print_all_errors();
    GC_INVOKE_FINALIZERS();
    DISABLE_SIGNALS();
    LOCK();
    op = GC_generic_malloc_words_small_inner(lw, k);
    UNLOCK();
    ENABLE_SIGNALS();
    return((ptr_t)op);
}

#if defined(THREADS) && !defined(SRC_M3)

extern signed_word GC_mem_found;   /* Protected by GC lock.  */

#ifdef PARALLEL_MARK
volatile signed_word GC_words_allocd_tmp = 0;
                        /* Number of words of memory allocated since    */
                        /* we released the GC lock.  Instead of         */
                        /* reacquiring the GC lock just to add this in, */
                        /* we add it in the next time we reacquire      */
                        /* the lock.  (Atomically adding it doesn't     */
                        /* work, since we would have to atomically      */
                        /* update it in GC_malloc, which is too         */
                        /* expensive.                                   */
#endif /* PARALLEL_MARK */

/* See reclaim.c: */
extern ptr_t GC_reclaim_generic();

/* Return a list of 1 or more objects of the indicated size, linked	*/
/* through the first word in the object.  This has the advantage that	*/
/* it acquires the allocation lock only once, and may greatly reduce	*/
/* time wasted contending for the allocation lock.  Typical usage would */
/* be in a thread that requires many items of the same size.  It would	*/
/* keep its own free list in thread-local storage, and call		*/
/* GC_malloc_many or friends to replenish it.  (We do not round up	*/
/* object sizes, since a call indicates the intention to consume many	*/
/* objects of exactly this size.)					*/
/* We return the free-list by assigning it to *result, since it is	*/
/* not safe to return, e.g. a linked list of pointer-free objects,	*/
/* since the collector would not retain the entire list if it were 	*/
/* invoked just as we were returning.					*/
/* Note that the client should usually clear the link field.		*/
void GC_generic_malloc_many(lb, k, result)
register word lb;
register int k;