malloc/obstack.c

   1 /* obstack.c - subroutines used implicitly by object stack macros
   2    Copyright (C) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1996, 1997,
   3    1998, 1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.  Its master source is NOT part of
   5    the C library, however.  The master source lives in /gd/gnu/lib.
   6
   7    The GNU C Library is free software; you can redistribute it and/or
   8    modify it under the terms of the GNU Lesser General Public
   9    License as published by the Free Software Foundation; either
  10    version 2.1 of the 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    Lesser General Public License for more details.
  16
  17    You should have received a copy of the GNU Lesser General Public
  18    License along with the GNU C Library; if not, write to the Free
  19    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  20    02111-1307 USA.  */
  21
  22 #ifdef HAVE_CONFIG_H
  23 # include <config.h>
  24 #endif
  25
  26 #ifdef _LIBC
  27 # include <obstack.h>
  28 # include <shlib-compat.h>
  29 #else
  30 # include "obstack.h"
  31 #endif
  32
  33 /* NOTE BEFORE MODIFYING THIS FILE: This version number must be
  34    incremented whenever callers compiled using an old obstack.h can no
  35    longer properly call the functions in this obstack.c.  */
  36 #define OBSTACK_INTERFACE_VERSION 1
  37
  38 /* Comment out all this code if we are using the GNU C Library, and are not
  39    actually compiling the library itself, and the installed library
  40    supports the same library interface we do.  This code is part of the GNU
  41    C Library, but also included in many other GNU distributions.  Compiling
  42    and linking in this code is a waste when using the GNU C library
  43    (especially if it is a shared library).  Rather than having every GNU
  44    program understand `configure --with-gnu-libc' and omit the object
  45    files, it is simpler to just do this in the source for each such file.  */
  46
  47 #include <stdio.h>              /* Random thing to get __GNU_LIBRARY__.  */
  48 #if !defined _LIBC && defined __GNU_LIBRARY__ && __GNU_LIBRARY__ > 1
  49 # include <gnu-versions.h>
  50 # if _GNU_OBSTACK_INTERFACE_VERSION == OBSTACK_INTERFACE_VERSION
  51 #  define ELIDE_CODE
  52 # endif
  53 #endif
  54
  55 #if defined _LIBC && defined USE_IN_LIBIO
  56 # include <wchar.h>
  57 #endif
  58
  59 #ifndef ELIDE_CODE
  60
  61
  62 /* Determine default alignment.  */
  63 struct fooalign {char x; double d;};
  64 # define DEFAULT_ALIGNMENT  \
  65   ((PTR_INT_TYPE) ((char *) &((struct fooalign *) 0)->d - (char *) 0))
  66 /* If malloc were really smart, it would round addresses to DEFAULT_ALIGNMENT.
  67    But in fact it might be less smart and round addresses to as much as
  68    DEFAULT_ROUNDING.  So we prepare for it to do that.  */
  69 union fooround {long x; double d;};
  70 # define DEFAULT_ROUNDING (sizeof (union fooround))
  71
  72 /* When we copy a long block of data, this is the unit to do it with.
  73    On some machines, copying successive ints does not work;
  74    in such a case, redefine COPYING_UNIT to `long' (if that works)
  75    or `char' as a last resort.  */
  76 # ifndef COPYING_UNIT
  77 #  define COPYING_UNIT int
  78 # endif
  79
  80
  81 /* The functions allocating more room by calling `obstack_chunk_alloc'
  82    jump to the handler pointed to by `obstack_alloc_failed_handler'.
  83    This can be set to a user defined function which should either
  84    abort gracefully or use longjump - but shouldn't return.  This
  85    variable by default points to the internal function
  86    `print_and_abort'.  */
  87 static void print_and_abort (void);
  88 void (*obstack_alloc_failed_handler) (void) = print_and_abort;
  89
  90 /* Exit value used when `print_and_abort' is used.  */
  91 # include <stdlib.h>
  92 # ifdef _LIBC
  93 int obstack_exit_failure = EXIT_FAILURE;
  94 # else
  95 #  include "exitfail.h"
  96 #  define obstack_exit_failure exit_failure
  97 # endif
  98
  99 # ifdef _LIBC
 100 #  if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_3_4)
 101 /* A looong time ago (before 1994, anyway; we're not sure) this global variable
 102    was used by non-GNU-C macros to avoid multiple evaluation.  The GNU C
 103    library still exports it because somebody might use it.  */
 104 struct obstack *_obstack_compat;
 105 compat_symbol (libc, _obstack_compat, _obstack, GLIBC_2_0);
 106 #  endif
 107 # endif
 108
 109 /* Define a macro that either calls functions with the traditional malloc/free
 110    calling interface, or calls functions with the mmalloc/mfree interface
 111    (that adds an extra first argument), based on the state of use_extra_arg.
 112    For free, do not use ?:, since some compilers, like the MIPS compilers,
 113    do not allow (expr) ? void : void.  */
 114
 115 # define CALL_CHUNKFUN(h, size) \
 116   (((h) -> use_extra_arg) \
 117    ? (*(h)->chunkfun) ((h)->extra_arg, (size)) \
 118    : (*(struct _obstack_chunk *(*) (long)) (h)->chunkfun) ((size)))
 119
 120 # define CALL_FREEFUN(h, old_chunk) \
 121   do { \
 122     if ((h) -> use_extra_arg) \
 123       (*(h)->freefun) ((h)->extra_arg, (old_chunk)); \
 124     else \
 125       (*(void (*) (void *)) (h)->freefun) ((old_chunk)); \
 126   } while (0)
 127
 128 \f
 129 /* Initialize an obstack H for use.  Specify chunk size SIZE (0 means default).
 130    Objects start on multiples of ALIGNMENT (0 means use default).
 131    CHUNKFUN is the function to use to allocate chunks,
 132    and FREEFUN the function to free them.
 133
 134    Return nonzero if successful, calls obstack_alloc_failed_handler if
 135    allocation fails.  */
 136
 137 int
 138 _obstack_begin (struct obstack *h,
 139                 int size, int alignment,
 140                 void *(*chunkfun) (long),
 141                 void (*freefun) (void *))
 142 {
 143   register struct _obstack_chunk *chunk; /* points to new chunk */
 144
 145   if (alignment == 0)
 146     alignment = (int) DEFAULT_ALIGNMENT;
 147   if (size == 0)
 148     /* Default size is what GNU malloc can fit in a 4096-byte block.  */
 149     {
 150       /* 12 is sizeof (mhead) and 4 is EXTRA from GNU malloc.
 151          Use the values for range checking, because if range checking is off,
 152          the extra bytes won't be missed terribly, but if range checking is on
 153          and we used a larger request, a whole extra 4096 bytes would be
 154          allocated.
 155
 156          These number are irrelevant to the new GNU malloc.  I suspect it is
 157          less sensitive to the size of the request.  */
 158       int extra = ((((12 + DEFAULT_ROUNDING - 1) & ~(DEFAULT_ROUNDING - 1))
 159                     + 4 + DEFAULT_ROUNDING - 1)
 160                    & ~(DEFAULT_ROUNDING - 1));
 161       size = 4096 - extra;
 162     }
 163
 164   h->chunkfun = (struct _obstack_chunk * (*)(void *, long)) chunkfun;
 165   h->freefun = (void (*) (void *, struct _obstack_chunk *)) freefun;
 166   h->chunk_size = size;
 167   h->alignment_mask = alignment - 1;
 168   h->use_extra_arg = 0;
 169
 170   chunk = h->chunk = CALL_CHUNKFUN (h, h -> chunk_size);
 171   if (!chunk)
 172     (*obstack_alloc_failed_handler) ();
 173   h->next_free = h->object_base = chunk->contents;
 174   h->chunk_limit = chunk->limit
 175     = (char *) chunk + h->chunk_size;
 176   chunk->prev = 0;
 177   /* The initial chunk now contains no empty object.  */
 178   h->maybe_empty_object = 0;
 179   h->alloc_failed = 0;
 180   return 1;
 181 }
 182
 183 int
 184 _obstack_begin_1 (struct obstack *h, int size, int alignment,
 185                   void *(*chunkfun) (void *, long),
 186                   void (*freefun) (void *, void *),
 187                   void *arg)
 188 {
 189   register struct _obstack_chunk *chunk; /* points to new chunk */
 190
 191   if (alignment == 0)
 192     alignment = (int) DEFAULT_ALIGNMENT;
 193   if (size == 0)
 194     /* Default size is what GNU malloc can fit in a 4096-byte block.  */
 195     {
 196       /* 12 is sizeof (mhead) and 4 is EXTRA from GNU malloc.
 197          Use the values for range checking, because if range checking is off,
 198          the extra bytes won't be missed terribly, but if range checking is on
 199          and we used a larger request, a whole extra 4096 bytes would be
 200          allocated.
 201
 202          These number are irrelevant to the new GNU malloc.  I suspect it is
 203          less sensitive to the size of the request.  */
 204       int extra = ((((12 + DEFAULT_ROUNDING - 1) & ~(DEFAULT_ROUNDING - 1))
 205                     + 4 + DEFAULT_ROUNDING - 1)
 206                    & ~(DEFAULT_ROUNDING - 1));
 207       size = 4096 - extra;
 208     }
 209
 210   h->chunkfun = (struct _obstack_chunk * (*)(void *,long)) chunkfun;
 211   h->freefun = (void (*) (void *, struct _obstack_chunk *)) freefun;
 212   h->chunk_size = size;
 213   h->alignment_mask = alignment - 1;
 214   h->extra_arg = arg;
 215   h->use_extra_arg = 1;
 216
 217   chunk = h->chunk = CALL_CHUNKFUN (h, h -> chunk_size);
 218   if (!chunk)
 219     (*obstack_alloc_failed_handler) ();
 220   h->next_free = h->object_base = chunk->contents;
 221   h->chunk_limit = chunk->limit
 222     = (char *) chunk + h->chunk_size;
 223   chunk->prev = 0;
 224   /* The initial chunk now contains no empty object.  */
 225   h->maybe_empty_object = 0;
 226   h->alloc_failed = 0;
 227   return 1;
 228 }
 229
 230 /* Allocate a new current chunk for the obstack *H
 231    on the assumption that LENGTH bytes need to be added
 232    to the current object, or a new object of length LENGTH allocated.
 233    Copies any partial object from the end of the old chunk
 234    to the beginning of the new one.  */
 235
 236 void
 237 _obstack_newchunk (struct obstack *h, int length)
 238 {
 239   register struct _obstack_chunk *old_chunk = h->chunk;
 240   register struct _obstack_chunk *new_chunk;
 241   register long new_size;
 242   register long obj_size = h->next_free - h->object_base;
 243   register long i;
 244   long already;
 245   char *object_base;
 246
 247   /* Compute size for new chunk.  */
 248   new_size = (obj_size + length) + (obj_size >> 3) + h->alignment_mask + 100;
 249   if (new_size < h->chunk_size)
 250     new_size = h->chunk_size;
 251
 252   /* Allocate and initialize the new chunk.  */
 253   new_chunk = CALL_CHUNKFUN (h, new_size);
 254   if (!new_chunk)
 255     (*obstack_alloc_failed_handler) ();
 256   h->chunk = new_chunk;
 257   new_chunk->prev = old_chunk;
 258   new_chunk->limit = h->chunk_limit = (char *) new_chunk + new_size;
 259
 260   /* Compute an aligned object_base in the new chunk */
 261   object_base =
 262     __INT_TO_PTR ((__PTR_TO_INT (new_chunk->contents) + h->alignment_mask)
 263                   & ~ (h->alignment_mask));
 264
 265   /* Move the existing object to the new chunk.
 266      Word at a time is fast and is safe if the object
 267      is sufficiently aligned.  */
 268   if (h->alignment_mask + 1 >= DEFAULT_ALIGNMENT)
 269     {
 270       for (i = obj_size / sizeof (COPYING_UNIT) - 1;
 271            i >= 0; i--)
 272         ((COPYING_UNIT *)object_base)[i]
 273           = ((COPYING_UNIT *)h->object_base)[i];
 274       /* We used to copy the odd few remaining bytes as one extra COPYING_UNIT,
 275          but that can cross a page boundary on a machine
 276          which does not do strict alignment for COPYING_UNITS.  */
 277       already = obj_size / sizeof (COPYING_UNIT) * sizeof (COPYING_UNIT);
 278     }
 279   else
 280     already = 0;
 281   /* Copy remaining bytes one by one.  */
 282   for (i = already; i < obj_size; i++)
 283     object_base[i] = h->object_base[i];
 284
 285   /* If the object just copied was the only data in OLD_CHUNK,
 286      free that chunk and remove it from the chain.
 287      But not if that chunk might contain an empty object.  */
 288   if (h->object_base == old_chunk->contents && ! h->maybe_empty_object)
 289     {
 290       new_chunk->prev = old_chunk->prev;
 291       CALL_FREEFUN (h, old_chunk);
 292     }
 293
 294   h->object_base = object_base;
 295   h->next_free = h->object_base + obj_size;
 296   /* The new chunk certainly contains no empty object yet.  */
 297   h->maybe_empty_object = 0;
 298 }
 299 # ifdef _LIBC
 300 libc_hidden_def (_obstack_newchunk)
 301 # endif
 302
 303 /* Return nonzero if object OBJ has been allocated from obstack H.
 304    This is here for debugging.
 305    If you use it in a program, you are probably losing.  */
 306
 307 /* Suppress -Wmissing-prototypes warning.  We don't want to declare this in
 308    obstack.h because it is just for debugging.  */
 309 int _obstack_allocated_p (struct obstack *h, void *obj);
 310
 311 int
 312 _obstack_allocated_p (struct obstack *h, void *obj)
 313 {
 314   register struct _obstack_chunk *lp;   /* below addr of any objects in this chunk */
 315   register struct _obstack_chunk *plp;  /* point to previous chunk if any */
 316
 317   lp = (h)->chunk;
 318   /* We use >= rather than > since the object cannot be exactly at
 319      the beginning of the chunk but might be an empty object exactly
 320      at the end of an adjacent chunk.  */
 321   while (lp != 0 && ((void *) lp >= obj || (void *) (lp)->limit < obj))
 322     {
 323       plp = lp->prev;
 324       lp = plp;
 325     }
 326   return lp != 0;
 327 }
 328 \f
 329 /* Free objects in obstack H, including OBJ and everything allocate
 330    more recently than OBJ.  If OBJ is zero, free everything in H.  */
 331
 332 # undef obstack_free
 333
 334 void
 335 obstack_free (struct obstack *h, void *obj)
 336 {
 337   register struct _obstack_chunk *lp;   /* below addr of any objects in this chunk */
 338   register struct _obstack_chunk *plp;  /* point to previous chunk if any */
 339
 340   lp = h->chunk;
 341   /* We use >= because there cannot be an object at the beginning of a chunk.
 342      But there can be an empty object at that address
 343      at the end of another chunk.  */
 344   while (lp != 0 && ((void *) lp >= obj || (void *) (lp)->limit < obj))
 345     {
 346       plp = lp->prev;
 347       CALL_FREEFUN (h, lp);
 348       lp = plp;
 349       /* If we switch chunks, we can't tell whether the new current
 350          chunk contains an empty object, so assume that it may.  */
 351       h->maybe_empty_object = 1;
 352     }
 353   if (lp)
 354     {
 355       h->object_base = h->next_free = (char *) (obj);
 356       h->chunk_limit = lp->limit;
 357       h->chunk = lp;
 358     }
 359   else if (obj != 0)
 360     /* obj is not in any of the chunks! */
 361     abort ();
 362 }
 363
 364 # ifdef _LIBC
 365 /* Older versions of libc used a function _obstack_free intended to be
 366    called by non-GCC compilers.  */
 367 strong_alias (obstack_free, _obstack_free)
 368 # endif
 369 \f
 370 int
 371 _obstack_memory_used (struct obstack *h)
 372 {
 373   register struct _obstack_chunk* lp;
 374   register int nbytes = 0;
 375
 376   for (lp = h->chunk; lp != 0; lp = lp->prev)
 377     {
 378       nbytes += lp->limit - (char *) lp;
 379     }
 380   return nbytes;
 381 }
 382 \f
 383 /* Define the error handler.  */
 384 # ifdef _LIBC
 385 #  include <libintl.h>
 386 # else
 387 #  include "gettext.h"
 388 # endif
 389 # ifndef _
 390 #  define _(msgid) gettext (msgid)
 391 # endif
 392
 393 # ifdef _LIBC
 394 #  include <libio/iolibio.h>
 395 # endif
 396
 397 # ifndef __attribute__
 398 /* This feature is available in gcc versions 2.5 and later.  */
 399 #  if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 5)
 400 #   define __attribute__(Spec) /* empty */
 401 #  endif
 402 # endif
 403
 404 static void
 405 __attribute__ ((noreturn))
 406 print_and_abort (void)
 407 {
 408   /* Don't change any of these strings.  Yes, it would be possible to add
 409      the newline to the string and use fputs or so.  But this must not
 410      happen because the "memory exhausted" message appears in other places
 411      like this and the translation should be reused instead of creating
 412      a very similar string which requires a separate translation.  */
 413 # if defined _LIBC && defined USE_IN_LIBIO
 414   if (_IO_fwide (stderr, 0) > 0)
 415     __fwprintf (stderr, L"%s\n", _("memory exhausted"));
 416   else
 417 # endif
 418     fprintf (stderr, "%s\n", _("memory exhausted"));
 419   exit (obstack_exit_failure);
 420 }
 421
 422 #endif  /* !ELIDE_CODE */