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Remove dependency on glibc malloc internals.
* alloc.c (XMALLOC_OVERRUN_CHECK_OVERHEAD, XMALLOC_OVERRUN_CHECK_SIZE): Move back here from lisp.h, but with their new implementations. (XMALLOC_BASE_ALIGNMENT, COMMON_MULTIPLE, XMALLOC_HEADER_ALIGNMENT) (XMALLOC_OVERRUN_SIZE_SIZE): Move these new lisp.h macros here. * charset.c (charset_table_init): New static var. (syms_of_charset): Use it instead of xmalloc. This removes a dependency on glibc malloc internals. See Eli Zaretskii's comment in <http://lists.gnu.org/archive/html/emacs-devel/2011-09/msg00815.html>. * lisp.h (XMALLOC_OVERRUN_CHECK_OVERHEAD, XMALLOC_OVERRUN_CHECK_SIZE): Move back to alloc.c. (XMALLOC_BASE_ALIGNMENT, COMMON_MULTIPLE, XMALLOC_HEADER_ALIGNMENT) (XMALLOC_OVERRUN_SIZE_SIZE): Move to alloc.c.
This commit is contained in:
Paul Eggert
parent
cbc5ee224e
commit
f701dc2abb
4 changed files with 79 additions and 70 deletions
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@ -1,3 +1,19 @@
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2011-09-30 Paul Eggert <eggert@cs.ucla.edu>
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Remove dependency on glibc malloc internals.
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* alloc.c (XMALLOC_OVERRUN_CHECK_OVERHEAD, XMALLOC_OVERRUN_CHECK_SIZE):
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Move back here from lisp.h, but with their new implementations.
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(XMALLOC_BASE_ALIGNMENT, COMMON_MULTIPLE, XMALLOC_HEADER_ALIGNMENT)
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(XMALLOC_OVERRUN_SIZE_SIZE): Move these new lisp.h macros here.
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* charset.c (charset_table_init): New static var.
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(syms_of_charset): Use it instead of xmalloc. This removes a
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dependency on glibc malloc internals. See Eli Zaretskii's comment in
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<http://lists.gnu.org/archive/html/emacs-devel/2011-09/msg00815.html>.
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* lisp.h (XMALLOC_OVERRUN_CHECK_OVERHEAD, XMALLOC_OVERRUN_CHECK_SIZE):
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Move back to alloc.c.
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(XMALLOC_BASE_ALIGNMENT, COMMON_MULTIPLE, XMALLOC_HEADER_ALIGNMENT)
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(XMALLOC_OVERRUN_SIZE_SIZE): Move to alloc.c.
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2011-09-30 Jan Djärv <jan.h.d@swipnet.se>
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* nsterm.m (windowDidResize): Call x_set_window_size only when
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47
src/alloc.c
47
src/alloc.c
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@ -482,10 +482,53 @@ buffer_memory_full (EMACS_INT nbytes)
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xsignal (Qnil, Vmemory_signal_data);
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}
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#ifdef XMALLOC_OVERRUN_CHECK
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#ifndef XMALLOC_OVERRUN_CHECK
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#define XMALLOC_OVERRUN_CHECK_OVERHEAD 0
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#else
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/* Check for overrun in malloc'ed buffers by wrapping a header and trailer
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around each block. */
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around each block.
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The header consists of XMALLOC_OVERRUN_CHECK_SIZE fixed bytes
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followed by XMALLOC_OVERRUN_SIZE_SIZE bytes containing the original
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block size in little-endian order. The trailer consists of
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XMALLOC_OVERRUN_CHECK_SIZE fixed bytes.
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The header is used to detect whether this block has been allocated
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through these functions, as some low-level libc functions may
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bypass the malloc hooks. */
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#define XMALLOC_OVERRUN_CHECK_SIZE 16
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#define XMALLOC_OVERRUN_CHECK_OVERHEAD \
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(2 * XMALLOC_OVERRUN_CHECK_SIZE + XMALLOC_OVERRUN_SIZE_SIZE)
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/* Define XMALLOC_OVERRUN_SIZE_SIZE so that (1) it's large enough to
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hold a size_t value and (2) the header size is a multiple of the
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alignment that Emacs needs for C types and for USE_LSB_TAG. */
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#define XMALLOC_BASE_ALIGNMENT \
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offsetof ( \
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struct { \
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union { long double d; intmax_t i; void *p; } u; \
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char c; \
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}, \
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c)
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#ifdef USE_LSB_TAG
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/* A common multiple of the positive integers A and B. Ideally this
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would be the least common multiple, but there's no way to do that
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as a constant expression in C, so do the best that we can easily do. */
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# define COMMON_MULTIPLE(a, b) \
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((a) % (b) == 0 ? (a) : (b) % (a) == 0 ? (b) : (a) * (b))
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# define XMALLOC_HEADER_ALIGNMENT \
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COMMON_MULTIPLE (1 << GCTYPEBITS, XMALLOC_BASE_ALIGNMENT)
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#else
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# define XMALLOC_HEADER_ALIGNMENT XMALLOC_BASE_ALIGNMENT
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#endif
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#define XMALLOC_OVERRUN_SIZE_SIZE \
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(((XMALLOC_OVERRUN_CHECK_SIZE + sizeof (size_t) \
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+ XMALLOC_HEADER_ALIGNMENT - 1) \
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/ XMALLOC_HEADER_ALIGNMENT * XMALLOC_HEADER_ALIGNMENT) \
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- XMALLOC_OVERRUN_CHECK_SIZE)
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static char const xmalloc_overrun_check_header[XMALLOC_OVERRUN_CHECK_SIZE] =
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{ '\x9a', '\x9b', '\xae', '\xaf',
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@ -1162,10 +1162,10 @@ usage: (define-charset-internal ...) */)
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sizeof *charset_table);
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memcpy (new_table, charset_table, old_size * sizeof *new_table);
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charset_table = new_table;
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/* FIXME: Doesn't this leak memory? The old charset_table becomes
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unreachable. It could be that this is intentional, because the
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old charset table may be in a dumped emacs, and reallocating such
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a table may not work. If the memory leak is intentional, a
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/* FIXME: This leaks memory, as the old charset_table becomes
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unreachable. If the old charset table is charset_table_init
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then this leak is intentional; otherwise, it's unclear.
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If the latter memory leak is intentional, a
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comment should be added to explain this. If not, the old
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charset_table should be freed, by passing it as the 1st argument
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to xpalloc and removing the memcpy. */
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@ -2327,22 +2327,21 @@ init_charset_once (void)
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#ifdef emacs
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/* Allocate an initial charset table that is large enough to handle
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Emacs while it is bootstrapping. As of September 2011, the size
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needs to be at least 166; make it a bit bigger to allow for future
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expansion.
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Don't make the value so small that the table is reallocated during
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bootstrapping, as glibc malloc calls larger than just under 64 KiB
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during an initial bootstrap wreak havoc after dumping; see the
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M_MMAP_THRESHOLD value in alloc.c, plus there is a extra overhead
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internal to glibc malloc and perhaps to Emacs malloc debugging. */
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static struct charset charset_table_init[180];
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void
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syms_of_charset (void)
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{
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/* Allocate an initial charset table that is just under 64 KiB in size.
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This should be large enough so that the charset table need not be
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reallocated during an initial bootstrap. Allocating anything larger than
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64 KiB in an initial run may not work, because glibc malloc might use
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mmap for larger allocations, and these don't work well across dumped
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systems. */
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enum {
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glibc_malloc_overhead = 3 * sizeof (size_t) - 1,
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initial_malloc_max =
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(1 << 16) - 1 - glibc_malloc_overhead - XMALLOC_OVERRUN_CHECK_OVERHEAD,
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charset_table_size_init = initial_malloc_max / sizeof (struct charset)
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};
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DEFSYM (Qcharsetp, "charsetp");
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DEFSYM (Qascii, "ascii");
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@ -2375,9 +2374,8 @@ syms_of_charset (void)
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Vcharset_hash_table = Fmake_hash_table (2, args);
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}
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charset_table = (struct charset *) xmalloc (sizeof (struct charset)
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* charset_table_size_init);
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charset_table_size = charset_table_size_init;
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charset_table = charset_table_init;
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charset_table_size = sizeof charset_table_init / sizeof *charset_table_init;
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charset_table_used = 0;
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defsubr (&Scharsetp);
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48
src/lisp.h
48
src/lisp.h
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@ -3568,54 +3568,6 @@ extern int initialized;
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extern int immediate_quit; /* Nonzero means ^G can quit instantly */
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/* Overhead for overrun check in malloc'ed buffers. The check
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operates by wrapping a header and trailer around each block.
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The header consists of XMALLOC_OVERRUN_CHECK_SIZE fixed bytes
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followed by XMALLOC_OVERRUN_SIZE_SIZE bytes containing the original
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block size in little-endian order. The trailer consists of
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XMALLOC_OVERRUN_CHECK_SIZE fixed bytes.
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The header is used to detect whether this block has been allocated
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through these functions, as some low-level libc functions may
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bypass the malloc hooks. */
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#ifndef XMALLOC_OVERRUN_CHECK
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# define XMALLOC_OVERRUN_CHECK_OVERHEAD 0
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#else
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# define XMALLOC_OVERRUN_CHECK_SIZE 16
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# define XMALLOC_OVERRUN_CHECK_OVERHEAD \
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(2 * XMALLOC_OVERRUN_CHECK_SIZE + XMALLOC_OVERRUN_SIZE_SIZE)
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/* Define XMALLOC_OVERRUN_SIZE_SIZE so that (1) it's large enough to
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hold a size_t value and (2) the header size is a multiple of the
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alignment that Emacs needs for C types and for USE_LSB_TAG. */
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# define XMALLOC_BASE_ALIGNMENT \
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offsetof ( \
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struct { \
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union { long double d; intmax_t i; void *p; } u; \
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char c; \
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}, \
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c)
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# ifdef USE_LSB_TAG
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/* A common multiple of the positive integers A and B. Ideally this
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would be the least common multiple, but there's no way to do that
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as a constant expression in C, so do the best that we can easily do. */
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# define COMMON_MULTIPLE(a, b) \
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((a) % (b) == 0 ? (a) : (b) % (a) == 0 ? (b) : (a) * (b))
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# define XMALLOC_HEADER_ALIGNMENT \
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COMMON_MULTIPLE (1 << GCTYPEBITS, XMALLOC_BASE_ALIGNMENT)
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# else
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# define XMALLOC_HEADER_ALIGNMENT XMALLOC_BASE_ALIGNMENT
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# endif
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# define XMALLOC_OVERRUN_SIZE_SIZE \
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(((XMALLOC_OVERRUN_CHECK_SIZE + sizeof (size_t) \
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+ XMALLOC_HEADER_ALIGNMENT - 1) \
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/ XMALLOC_HEADER_ALIGNMENT * XMALLOC_HEADER_ALIGNMENT) \
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- XMALLOC_OVERRUN_CHECK_SIZE)
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#endif
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extern POINTER_TYPE *xmalloc (size_t);
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extern POINTER_TYPE *xrealloc (POINTER_TYPE *, size_t);
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extern void xfree (POINTER_TYPE *);
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