1 /* obstack.c - subroutines used implicitly by object stack macros 2 3 Copyright (C) 1988-1994, 1996-2006, 2009-2012 Free Software Foundation, Inc. 4 5 This program is free software: you can redistribute it and/or modify 6 it under the terms of the GNU General Public License as published by 7 the Free Software Foundation; either version 3 of the License, or 8 (at your option) any later version. 9 10 This program is distributed in the hope that it will be useful, 11 but WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 GNU General Public License for more details. 14 15 You should have received a copy of the GNU General Public License 16 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 17 18 #ifdef _LIBC 19 # include <obstack.h> 20 # include <shlib-compat.h> 21 #else 22 # include <config.h> 23 # include "obstack.h" 24 #endif 25 26 /* NOTE BEFORE MODIFYING THIS FILE: This version number must be 27 incremented whenever callers compiled using an old obstack.h can no 28 longer properly call the functions in this obstack.c. */ 29 #define OBSTACK_INTERFACE_VERSION 1 30 31 /* Comment out all this code if we are using the GNU C Library, and are not 32 actually compiling the library itself, and the installed library 33 supports the same library interface we do. This code is part of the GNU 34 C Library, but also included in many other GNU distributions. Compiling 35 and linking in this code is a waste when using the GNU C library 36 (especially if it is a shared library). Rather than having every GNU 37 program understand 'configure --with-gnu-libc' and omit the object 38 files, it is simpler to just do this in the source for each such file. */ 39 40 #include <stdio.h> /* Random thing to get __GNU_LIBRARY__. */ 41 #if !defined _LIBC && defined __GNU_LIBRARY__ && __GNU_LIBRARY__ > 1 42 # include <gnu-versions.h> 43 # if _GNU_OBSTACK_INTERFACE_VERSION == OBSTACK_INTERFACE_VERSION 44 # define ELIDE_CODE 45 # endif 46 #endif 47 48 #include <stddef.h> 49 50 #ifndef ELIDE_CODE 51 52 # include <stdint.h> 53 54 /* Determine default alignment. */ 55 union fooround 56 { 57 uintmax_t i; 58 long double d; 59 void *p; 60 }; 61 struct fooalign 62 { 63 char c; 64 union fooround u; 65 }; 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 enum 70 { 71 DEFAULT_ALIGNMENT = offsetof (struct fooalign, u), 72 DEFAULT_ROUNDING = sizeof (union fooround) 73 }; 74 75 /* When we copy a long block of data, this is the unit to do it with. 76 On some machines, copying successive ints does not work; 77 in such a case, redefine COPYING_UNIT to 'long' (if that works) 78 or 'char' as a last resort. */ 79 # ifndef COPYING_UNIT 80 # define COPYING_UNIT int 81 # endif 82 83 84 /* The functions allocating more room by calling 'obstack_chunk_alloc' 85 jump to the handler pointed to by 'obstack_alloc_failed_handler'. 86 This can be set to a user defined function which should either 87 abort gracefully or use longjump - but shouldn't return. This 88 variable by default points to the internal function 89 'print_and_abort'. */ 90 static _Noreturn void print_and_abort (void); 91 void (*obstack_alloc_failed_handler) (void) = print_and_abort; 92 93 /* Exit value used when 'print_and_abort' is used. */ 94 # include <stdlib.h> 95 # ifdef _LIBC 96 int obstack_exit_failure = EXIT_FAILURE; 97 # else 98 # include "exitfail.h" 99 # define obstack_exit_failure exit_failure 100 # endif 101 102 # ifdef _LIBC 103 # if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_3_4) 104 /* A looong time ago (before 1994, anyway; we're not sure) this global variable 105 was used by non-GNU-C macros to avoid multiple evaluation. The GNU C 106 library still exports it because somebody might use it. */ 107 struct obstack *_obstack_compat; 108 compat_symbol (libc, _obstack_compat, _obstack, GLIBC_2_0); 109 # endif 110 # endif 111 112 /* Define a macro that either calls functions with the traditional malloc/free 113 calling interface, or calls functions with the mmalloc/mfree interface 114 (that adds an extra first argument), based on the state of use_extra_arg. 115 For free, do not use ?:, since some compilers, like the MIPS compilers, 116 do not allow (expr) ? void : void. */ 117 118 # define CALL_CHUNKFUN(h, size) \ 119 (((h) -> use_extra_arg) \ 120 ? (*(h)->chunkfun) ((h)->extra_arg, (size)) \ 121 : (*(struct _obstack_chunk *(*) (long)) (h)->chunkfun) ((size))) 122 123 # define CALL_FREEFUN(h, old_chunk) \ 124 do { \ 125 if ((h) -> use_extra_arg) \ 126 (*(h)->freefun) ((h)->extra_arg, (old_chunk)); \ 127 else \ 128 (*(void (*) (void *)) (h)->freefun) ((old_chunk)); \ 129 } while (0) 130 131 132 /* Initialize an obstack H for use. Specify chunk size SIZE (0 means default). 134 Objects start on multiples of ALIGNMENT (0 means use default). 135 CHUNKFUN is the function to use to allocate chunks, 136 and FREEFUN the function to free them. 137 138 Return nonzero if successful, calls obstack_alloc_failed_handler if 139 allocation fails. */ 140 141 int 142 _obstack_begin (struct obstack *h, 143 int size, int alignment, 144 void *(*chunkfun) (long), 145 void (*freefun) (void *)) 146 { 147 register struct _obstack_chunk *chunk; /* points to new chunk */ 148 149 if (alignment == 0) 150 alignment = DEFAULT_ALIGNMENT; 151 if (size == 0) 152 /* Default size is what GNU malloc can fit in a 4096-byte block. */ 153 { 154 /* 12 is sizeof (mhead) and 4 is EXTRA from GNU malloc. 155 Use the values for range checking, because if range checking is off, 156 the extra bytes won't be missed terribly, but if range checking is on 157 and we used a larger request, a whole extra 4096 bytes would be 158 allocated. 159 160 These number are irrelevant to the new GNU malloc. I suspect it is 161 less sensitive to the size of the request. */ 162 int extra = ((((12 + DEFAULT_ROUNDING - 1) & ~(DEFAULT_ROUNDING - 1)) 163 + 4 + DEFAULT_ROUNDING - 1) 164 & ~(DEFAULT_ROUNDING - 1)); 165 size = 4096 - extra; 166 } 167 168 h->chunkfun = (struct _obstack_chunk * (*)(void *, long)) chunkfun; 169 h->freefun = (void (*) (void *, struct _obstack_chunk *)) freefun; 170 h->chunk_size = size; 171 h->alignment_mask = alignment - 1; 172 h->use_extra_arg = 0; 173 174 chunk = h->chunk = CALL_CHUNKFUN (h, h -> chunk_size); 175 if (!chunk) 176 (*obstack_alloc_failed_handler) (); 177 h->next_free = h->object_base = __PTR_ALIGN ((char *) chunk, chunk->contents, 178 alignment - 1); 179 h->chunk_limit = chunk->limit 180 = (char *) chunk + h->chunk_size; 181 chunk->prev = 0; 182 /* The initial chunk now contains no empty object. */ 183 h->maybe_empty_object = 0; 184 h->alloc_failed = 0; 185 return 1; 186 } 187 188 int 189 _obstack_begin_1 (struct obstack *h, int size, int alignment, 190 void *(*chunkfun) (void *, long), 191 void (*freefun) (void *, void *), 192 void *arg) 193 { 194 register struct _obstack_chunk *chunk; /* points to new chunk */ 195 196 if (alignment == 0) 197 alignment = DEFAULT_ALIGNMENT; 198 if (size == 0) 199 /* Default size is what GNU malloc can fit in a 4096-byte block. */ 200 { 201 /* 12 is sizeof (mhead) and 4 is EXTRA from GNU malloc. 202 Use the values for range checking, because if range checking is off, 203 the extra bytes won't be missed terribly, but if range checking is on 204 and we used a larger request, a whole extra 4096 bytes would be 205 allocated. 206 207 These number are irrelevant to the new GNU malloc. I suspect it is 208 less sensitive to the size of the request. */ 209 int extra = ((((12 + DEFAULT_ROUNDING - 1) & ~(DEFAULT_ROUNDING - 1)) 210 + 4 + DEFAULT_ROUNDING - 1) 211 & ~(DEFAULT_ROUNDING - 1)); 212 size = 4096 - extra; 213 } 214 215 h->chunkfun = (struct _obstack_chunk * (*)(void *,long)) chunkfun; 216 h->freefun = (void (*) (void *, struct _obstack_chunk *)) freefun; 217 h->chunk_size = size; 218 h->alignment_mask = alignment - 1; 219 h->extra_arg = arg; 220 h->use_extra_arg = 1; 221 222 chunk = h->chunk = CALL_CHUNKFUN (h, h -> chunk_size); 223 if (!chunk) 224 (*obstack_alloc_failed_handler) (); 225 h->next_free = h->object_base = __PTR_ALIGN ((char *) chunk, chunk->contents, 226 alignment - 1); 227 h->chunk_limit = chunk->limit 228 = (char *) chunk + h->chunk_size; 229 chunk->prev = 0; 230 /* The initial chunk now contains no empty object. */ 231 h->maybe_empty_object = 0; 232 h->alloc_failed = 0; 233 return 1; 234 } 235 236 /* Allocate a new current chunk for the obstack *H 237 on the assumption that LENGTH bytes need to be added 238 to the current object, or a new object of length LENGTH allocated. 239 Copies any partial object from the end of the old chunk 240 to the beginning of the new one. */ 241 242 void 243 _obstack_newchunk (struct obstack *h, int length) 244 { 245 register struct _obstack_chunk *old_chunk = h->chunk; 246 register struct _obstack_chunk *new_chunk; 247 register long new_size; 248 register long obj_size = h->next_free - h->object_base; 249 register long i; 250 long already; 251 char *object_base; 252 253 /* Compute size for new chunk. */ 254 new_size = (obj_size + length) + (obj_size >> 3) + h->alignment_mask + 100; 255 if (new_size < h->chunk_size) 256 new_size = h->chunk_size; 257 258 /* Allocate and initialize the new chunk. */ 259 new_chunk = CALL_CHUNKFUN (h, new_size); 260 if (!new_chunk) 261 (*obstack_alloc_failed_handler) (); 262 h->chunk = new_chunk; 263 new_chunk->prev = old_chunk; 264 new_chunk->limit = h->chunk_limit = (char *) new_chunk + new_size; 265 266 /* Compute an aligned object_base in the new chunk */ 267 object_base = 268 __PTR_ALIGN ((char *) new_chunk, new_chunk->contents, h->alignment_mask); 269 270 /* Move the existing object to the new chunk. 271 Word at a time is fast and is safe if the object 272 is sufficiently aligned. */ 273 if (h->alignment_mask + 1 >= DEFAULT_ALIGNMENT) 274 { 275 for (i = obj_size / sizeof (COPYING_UNIT) - 1; 276 i >= 0; i--) 277 ((COPYING_UNIT *)object_base)[i] 278 = ((COPYING_UNIT *)h->object_base)[i]; 279 /* We used to copy the odd few remaining bytes as one extra COPYING_UNIT, 280 but that can cross a page boundary on a machine 281 which does not do strict alignment for COPYING_UNITS. */ 282 already = obj_size / sizeof (COPYING_UNIT) * sizeof (COPYING_UNIT); 283 } 284 else 285 already = 0; 286 /* Copy remaining bytes one by one. */ 287 for (i = already; i < obj_size; i++) 288 object_base[i] = h->object_base[i]; 289 290 /* If the object just copied was the only data in OLD_CHUNK, 291 free that chunk and remove it from the chain. 292 But not if that chunk might contain an empty object. */ 293 if (! h->maybe_empty_object 294 && (h->object_base 295 == __PTR_ALIGN ((char *) old_chunk, old_chunk->contents, 296 h->alignment_mask))) 297 { 298 new_chunk->prev = old_chunk->prev; 299 CALL_FREEFUN (h, old_chunk); 300 } 301 302 h->object_base = object_base; 303 h->next_free = h->object_base + obj_size; 304 /* The new chunk certainly contains no empty object yet. */ 305 h->maybe_empty_object = 0; 306 } 307 # ifdef _LIBC 308 libc_hidden_def (_obstack_newchunk) 309 # endif 310 311 /* Return nonzero if object OBJ has been allocated from obstack H. 312 This is here for debugging. 313 If you use it in a program, you are probably losing. */ 314 315 /* Suppress -Wmissing-prototypes warning. We don't want to declare this in 316 obstack.h because it is just for debugging. */ 317 int _obstack_allocated_p (struct obstack *h, void *obj); 318 319 int 320 _obstack_allocated_p (struct obstack *h, void *obj) 321 { 322 register struct _obstack_chunk *lp; /* below addr of any objects in this chunk */ 323 register struct _obstack_chunk *plp; /* point to previous chunk if any */ 324 325 lp = (h)->chunk; 326 /* We use >= rather than > since the object cannot be exactly at 327 the beginning of the chunk but might be an empty object exactly 328 at the end of an adjacent chunk. */ 329 while (lp != 0 && ((void *) lp >= obj || (void *) (lp)->limit < obj)) 330 { 331 plp = lp->prev; 332 lp = plp; 333 } 334 return lp != 0; 335 } 336 337 /* Free objects in obstack H, including OBJ and everything allocate 339 more recently than OBJ. If OBJ is zero, free everything in H. */ 340 341 # undef obstack_free 342 343 void 344 __obstack_free (struct obstack *h, void *obj) 345 { 346 register struct _obstack_chunk *lp; /* below addr of any objects in this chunk */ 347 register struct _obstack_chunk *plp; /* point to previous chunk if any */ 348 349 lp = h->chunk; 350 /* We use >= because there cannot be an object at the beginning of a chunk. 351 But there can be an empty object at that address 352 at the end of another chunk. */ 353 while (lp != 0 && ((void *) lp >= obj || (void *) (lp)->limit < obj)) 354 { 355 plp = lp->prev; 356 CALL_FREEFUN (h, lp); 357 lp = plp; 358 /* If we switch chunks, we can't tell whether the new current 359 chunk contains an empty object, so assume that it may. */ 360 h->maybe_empty_object = 1; 361 } 362 if (lp) 363 { 364 h->object_base = h->next_free = (char *) (obj); 365 h->chunk_limit = lp->limit; 366 h->chunk = lp; 367 } 368 else if (obj != 0) 369 /* obj is not in any of the chunks! */ 370 abort (); 371 } 372 373 # ifdef _LIBC 374 /* Older versions of libc used a function _obstack_free intended to be 375 called by non-GCC compilers. */ 376 strong_alias (obstack_free, _obstack_free) 377 # endif 378 379 int 381 _obstack_memory_used (struct obstack *h) 382 { 383 register struct _obstack_chunk* lp; 384 register int nbytes = 0; 385 386 for (lp = h->chunk; lp != 0; lp = lp->prev) 387 { 388 nbytes += lp->limit - (char *) lp; 389 } 390 return nbytes; 391 } 392 393 /* Define the error handler. */ 395 # ifdef _LIBC 396 # include <libintl.h> 397 # else 398 # include "gettext.h" 399 # endif 400 # ifndef _ 401 # define _(msgid) gettext (msgid) 402 # endif 403 404 # ifdef _LIBC 405 # include <libio/iolibio.h> 406 # endif 407 408 static _Noreturn void 409 print_and_abort (void) 410 { 411 /* Don't change any of these strings. Yes, it would be possible to add 412 the newline to the string and use fputs or so. But this must not 413 happen because the "memory exhausted" message appears in other places 414 like this and the translation should be reused instead of creating 415 a very similar string which requires a separate translation. */ 416 # ifdef _LIBC 417 (void) __fxprintf (NULL, "%s\n", _("memory exhausted")); 418 # else 419 fprintf (stderr, "%s\n", _("memory exhausted")); 420 # endif 421 exit (obstack_exit_failure); 422 } 423 424 #endif /* !ELIDE_CODE */ 425
