* intrinsic.h (gfc_simplify_mvbits): Remove.
[official-gcc.git] / include / obstack.h
blob9759af48ffea7179a2ae4f3a44e8bcbab7d7cf71
1 /* obstack.h - object stack macros
2 Copyright (C) 1988-2015 Free Software Foundation, Inc.
5 NOTE: The canonical source of this file is maintained with the GNU C Library.
6 Bugs can be reported to bug-glibc@gnu.org.
8 This program is free software; you can redistribute it and/or modify it
9 under the terms of the GNU General Public License as published by the
10 Free Software Foundation; either version 2, or (at your option) any
11 later version.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with this program; if not, write to the Free Software
20 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301,
21 USA. */
23 /* Summary:
25 All the apparent functions defined here are macros. The idea
26 is that you would use these pre-tested macros to solve a
27 very specific set of problems, and they would run fast.
28 Caution: no side-effects in arguments please!! They may be
29 evaluated MANY times!!
31 These macros operate a stack of objects. Each object starts life
32 small, and may grow to maturity. (Consider building a word syllable
33 by syllable.) An object can move while it is growing. Once it has
34 been "finished" it never changes address again. So the "top of the
35 stack" is typically an immature growing object, while the rest of the
36 stack is of mature, fixed size and fixed address objects.
38 These routines grab large chunks of memory, using a function you
39 supply, called `obstack_chunk_alloc'. On occasion, they free chunks,
40 by calling `obstack_chunk_free'. You must define them and declare
41 them before using any obstack macros.
43 Each independent stack is represented by a `struct obstack'.
44 Each of the obstack macros expects a pointer to such a structure
45 as the first argument.
47 One motivation for this package is the problem of growing char strings
48 in symbol tables. Unless you are "fascist pig with a read-only mind"
49 --Gosper's immortal quote from HAKMEM item 154, out of context--you
50 would not like to put any arbitrary upper limit on the length of your
51 symbols.
53 In practice this often means you will build many short symbols and a
54 few long symbols. At the time you are reading a symbol you don't know
55 how long it is. One traditional method is to read a symbol into a
56 buffer, realloc()ating the buffer every time you try to read a symbol
57 that is longer than the buffer. This is beaut, but you still will
58 want to copy the symbol from the buffer to a more permanent
59 symbol-table entry say about half the time.
61 With obstacks, you can work differently. Use one obstack for all symbol
62 names. As you read a symbol, grow the name in the obstack gradually.
63 When the name is complete, finalize it. Then, if the symbol exists already,
64 free the newly read name.
66 The way we do this is to take a large chunk, allocating memory from
67 low addresses. When you want to build a symbol in the chunk you just
68 add chars above the current "high water mark" in the chunk. When you
69 have finished adding chars, because you got to the end of the symbol,
70 you know how long the chars are, and you can create a new object.
71 Mostly the chars will not burst over the highest address of the chunk,
72 because you would typically expect a chunk to be (say) 100 times as
73 long as an average object.
75 In case that isn't clear, when we have enough chars to make up
76 the object, THEY ARE ALREADY CONTIGUOUS IN THE CHUNK (guaranteed)
77 so we just point to it where it lies. No moving of chars is
78 needed and this is the second win: potentially long strings need
79 never be explicitly shuffled. Once an object is formed, it does not
80 change its address during its lifetime.
82 When the chars burst over a chunk boundary, we allocate a larger
83 chunk, and then copy the partly formed object from the end of the old
84 chunk to the beginning of the new larger chunk. We then carry on
85 accreting characters to the end of the object as we normally would.
87 A special macro is provided to add a single char at a time to a
88 growing object. This allows the use of register variables, which
89 break the ordinary 'growth' macro.
91 Summary:
92 We allocate large chunks.
93 We carve out one object at a time from the current chunk.
94 Once carved, an object never moves.
95 We are free to append data of any size to the currently
96 growing object.
97 Exactly one object is growing in an obstack at any one time.
98 You can run one obstack per control block.
99 You may have as many control blocks as you dare.
100 Because of the way we do it, you can `unwind' an obstack
101 back to a previous state. (You may remove objects much
102 as you would with a stack.)
106 /* Don't do the contents of this file more than once. */
108 #ifndef _OBSTACK_H
109 #define _OBSTACK_H 1
111 #ifdef __cplusplus
112 extern "C" {
113 #endif
115 /* We use subtraction of (char *) 0 instead of casting to int
116 because on word-addressable machines a simple cast to int
117 may ignore the byte-within-word field of the pointer. */
119 #ifndef __PTR_TO_INT
120 # define __PTR_TO_INT(P) ((P) - (char *) 0)
121 #endif
123 #ifndef __INT_TO_PTR
124 # define __INT_TO_PTR(P) ((P) + (char *) 0)
125 #endif
127 /* We need the type of the resulting object. If __PTRDIFF_TYPE__ is
128 defined, as with GNU C, use that; that way we don't pollute the
129 namespace with <stddef.h>'s symbols. Otherwise, if <stddef.h> is
130 available, include it and use ptrdiff_t. In traditional C, long is
131 the best that we can do. */
133 #ifdef __PTRDIFF_TYPE__
134 # define PTR_INT_TYPE __PTRDIFF_TYPE__
135 #else
136 # ifdef HAVE_STDDEF_H
137 # include <stddef.h>
138 # define PTR_INT_TYPE ptrdiff_t
139 # else
140 # define PTR_INT_TYPE long
141 # endif
142 #endif
144 #if defined _LIBC || defined HAVE_STRING_H
145 # include <string.h>
146 # define _obstack_memcpy(To, From, N) memcpy ((To), (From), (N))
147 #else
148 # ifdef memcpy
149 # define _obstack_memcpy(To, From, N) memcpy ((To), (char *)(From), (N))
150 # else
151 # define _obstack_memcpy(To, From, N) bcopy ((char *)(From), (To), (N))
152 # endif
153 #endif
155 struct _obstack_chunk /* Lives at front of each chunk. */
157 char *limit; /* 1 past end of this chunk */
158 struct _obstack_chunk *prev; /* address of prior chunk or NULL */
159 char contents[4]; /* objects begin here */
162 struct obstack /* control current object in current chunk */
164 long chunk_size; /* preferred size to allocate chunks in */
165 struct _obstack_chunk *chunk; /* address of current struct obstack_chunk */
166 char *object_base; /* address of object we are building */
167 char *next_free; /* where to add next char to current object */
168 char *chunk_limit; /* address of char after current chunk */
169 PTR_INT_TYPE temp; /* Temporary for some macros. */
170 int alignment_mask; /* Mask of alignment for each object. */
171 /* These prototypes vary based on `use_extra_arg', and we use
172 casts to the prototypeless function type in all assignments,
173 but having prototypes here quiets -Wstrict-prototypes. */
174 struct _obstack_chunk *(*chunkfun) (void *, long);
175 void (*freefun) (void *, struct _obstack_chunk *);
176 void *extra_arg; /* first arg for chunk alloc/dealloc funcs */
177 unsigned use_extra_arg:1; /* chunk alloc/dealloc funcs take extra arg */
178 unsigned maybe_empty_object:1;/* There is a possibility that the current
179 chunk contains a zero-length object. This
180 prevents freeing the chunk if we allocate
181 a bigger chunk to replace it. */
182 unsigned alloc_failed:1; /* No longer used, as we now call the failed
183 handler on error, but retained for binary
184 compatibility. */
187 /* Declare the external functions we use; they are in obstack.c. */
189 extern void _obstack_newchunk (struct obstack *, int);
190 extern void _obstack_free (struct obstack *, void *);
191 extern int _obstack_begin (struct obstack *, int, int,
192 void *(*) (long), void (*) (void *));
193 extern int _obstack_begin_1 (struct obstack *, int, int,
194 void *(*) (void *, long),
195 void (*) (void *, void *), void *);
196 extern int _obstack_memory_used (struct obstack *);
198 /* Do the function-declarations after the structs
199 but before defining the macros. */
201 void obstack_init (struct obstack *obstack);
203 void * obstack_alloc (struct obstack *obstack, int size);
205 void * obstack_copy (struct obstack *obstack, void *address, int size);
206 void * obstack_copy0 (struct obstack *obstack, void *address, int size);
208 void obstack_free (struct obstack *obstack, void *block);
210 void obstack_blank (struct obstack *obstack, int size);
212 void obstack_grow (struct obstack *obstack, void *data, int size);
213 void obstack_grow0 (struct obstack *obstack, void *data, int size);
215 void obstack_1grow (struct obstack *obstack, int data_char);
216 void obstack_ptr_grow (struct obstack *obstack, void *data);
217 void obstack_int_grow (struct obstack *obstack, int data);
219 void * obstack_finish (struct obstack *obstack);
221 int obstack_object_size (struct obstack *obstack);
223 int obstack_room (struct obstack *obstack);
224 void obstack_make_room (struct obstack *obstack, int size);
225 void obstack_1grow_fast (struct obstack *obstack, int data_char);
226 void obstack_ptr_grow_fast (struct obstack *obstack, void *data);
227 void obstack_int_grow_fast (struct obstack *obstack, int data);
228 void obstack_blank_fast (struct obstack *obstack, int size);
230 void * obstack_base (struct obstack *obstack);
231 void * obstack_next_free (struct obstack *obstack);
232 int obstack_alignment_mask (struct obstack *obstack);
233 int obstack_chunk_size (struct obstack *obstack);
234 int obstack_memory_used (struct obstack *obstack);
236 /* Error handler called when `obstack_chunk_alloc' failed to allocate
237 more memory. This can be set to a user defined function. The
238 default action is to print a message and abort. */
239 extern void (*obstack_alloc_failed_handler) (void);
241 /* Exit value used when `print_and_abort' is used. */
242 extern int obstack_exit_failure;
244 /* Pointer to beginning of object being allocated or to be allocated next.
245 Note that this might not be the final address of the object
246 because a new chunk might be needed to hold the final size. */
248 #define obstack_base(h) ((h)->object_base)
250 /* Size for allocating ordinary chunks. */
252 #define obstack_chunk_size(h) ((h)->chunk_size)
254 /* Pointer to next byte not yet allocated in current chunk. */
256 #define obstack_next_free(h) ((h)->next_free)
258 /* Mask specifying low bits that should be clear in address of an object. */
260 #define obstack_alignment_mask(h) ((h)->alignment_mask)
262 /* To prevent prototype warnings provide complete argument list in
263 standard C version. */
264 # define obstack_init(h) \
265 _obstack_begin ((h), 0, 0, \
266 (void *(*) (long)) obstack_chunk_alloc, (void (*) (void *)) obstack_chunk_free)
268 # define obstack_begin(h, size) \
269 _obstack_begin ((h), (size), 0, \
270 (void *(*) (long)) obstack_chunk_alloc, (void (*) (void *)) obstack_chunk_free)
272 # define obstack_specify_allocation(h, size, alignment, chunkfun, freefun) \
273 _obstack_begin ((h), (size), (alignment), \
274 (void *(*) (long)) (chunkfun), (void (*) (void *)) (freefun))
276 # define obstack_specify_allocation_with_arg(h, size, alignment, chunkfun, freefun, arg) \
277 _obstack_begin_1 ((h), (size), (alignment), \
278 (void *(*) (void *, long)) (chunkfun), \
279 (void (*) (void *, void *)) (freefun), (arg))
281 # define obstack_chunkfun(h, newchunkfun) \
282 ((h) -> chunkfun = (struct _obstack_chunk *(*)(void *, long)) (newchunkfun))
284 # define obstack_freefun(h, newfreefun) \
285 ((h) -> freefun = (void (*)(void *, struct _obstack_chunk *)) (newfreefun))
287 #define obstack_1grow_fast(h,achar) (*((h)->next_free)++ = (achar))
289 #define obstack_blank_fast(h,n) ((h)->next_free += (n))
291 #define obstack_memory_used(h) _obstack_memory_used (h)
293 #if defined __GNUC__ && defined __STDC__ && __STDC__
294 /* NextStep 2.0 cc is really gcc 1.93 but it defines __GNUC__ = 2 and
295 does not implement __extension__. But that compiler doesn't define
296 __GNUC_MINOR__. */
297 # if __GNUC__ < 2 || (__NeXT__ && !__GNUC_MINOR__)
298 # define __extension__
299 # endif
301 /* For GNU C, if not -traditional,
302 we can define these macros to compute all args only once
303 without using a global variable.
304 Also, we can avoid using the `temp' slot, to make faster code. */
306 # define obstack_object_size(OBSTACK) \
307 __extension__ \
308 ({ struct obstack *__o = (OBSTACK); \
309 (unsigned) (__o->next_free - __o->object_base); })
311 # define obstack_room(OBSTACK) \
312 __extension__ \
313 ({ struct obstack *__o = (OBSTACK); \
314 (unsigned) (__o->chunk_limit - __o->next_free); })
316 # define obstack_make_room(OBSTACK,length) \
317 __extension__ \
318 ({ struct obstack *__o = (OBSTACK); \
319 int __len = (length); \
320 if (__o->chunk_limit - __o->next_free < __len) \
321 _obstack_newchunk (__o, __len); \
322 (void) 0; })
324 # define obstack_empty_p(OBSTACK) \
325 __extension__ \
326 ({ struct obstack *__o = (OBSTACK); \
327 (__o->chunk->prev == 0 && __o->next_free - __o->chunk->contents == 0); })
329 # define obstack_grow(OBSTACK,where,length) \
330 __extension__ \
331 ({ struct obstack *__o = (OBSTACK); \
332 int __len = (length); \
333 if (__o->next_free + __len > __o->chunk_limit) \
334 _obstack_newchunk (__o, __len); \
335 _obstack_memcpy (__o->next_free, (where), __len); \
336 __o->next_free += __len; \
337 (void) 0; })
339 # define obstack_grow0(OBSTACK,where,length) \
340 __extension__ \
341 ({ struct obstack *__o = (OBSTACK); \
342 int __len = (length); \
343 if (__o->next_free + __len + 1 > __o->chunk_limit) \
344 _obstack_newchunk (__o, __len + 1); \
345 _obstack_memcpy (__o->next_free, (where), __len); \
346 __o->next_free += __len; \
347 *(__o->next_free)++ = 0; \
348 (void) 0; })
350 # define obstack_1grow(OBSTACK,datum) \
351 __extension__ \
352 ({ struct obstack *__o = (OBSTACK); \
353 if (__o->next_free + 1 > __o->chunk_limit) \
354 _obstack_newchunk (__o, 1); \
355 obstack_1grow_fast (__o, datum); \
356 (void) 0; })
358 /* These assume that the obstack alignment is good enough for pointers or ints,
359 and that the data added so far to the current object
360 shares that much alignment. */
362 # define obstack_ptr_grow(OBSTACK,datum) \
363 __extension__ \
364 ({ struct obstack *__o = (OBSTACK); \
365 if (__o->next_free + sizeof (void *) > __o->chunk_limit) \
366 _obstack_newchunk (__o, sizeof (void *)); \
367 obstack_ptr_grow_fast (__o, datum); })
369 # define obstack_int_grow(OBSTACK,datum) \
370 __extension__ \
371 ({ struct obstack *__o = (OBSTACK); \
372 if (__o->next_free + sizeof (int) > __o->chunk_limit) \
373 _obstack_newchunk (__o, sizeof (int)); \
374 obstack_int_grow_fast (__o, datum); })
376 # define obstack_ptr_grow_fast(OBSTACK,aptr) \
377 __extension__ \
378 ({ struct obstack *__o1 = (OBSTACK); \
379 *(const void **) __o1->next_free = (aptr); \
380 __o1->next_free += sizeof (const void *); \
381 (void) 0; })
383 # define obstack_int_grow_fast(OBSTACK,aint) \
384 __extension__ \
385 ({ struct obstack *__o1 = (OBSTACK); \
386 *(int *) __o1->next_free = (aint); \
387 __o1->next_free += sizeof (int); \
388 (void) 0; })
390 # define obstack_blank(OBSTACK,length) \
391 __extension__ \
392 ({ struct obstack *__o = (OBSTACK); \
393 int __len = (length); \
394 if (__o->chunk_limit - __o->next_free < __len) \
395 _obstack_newchunk (__o, __len); \
396 obstack_blank_fast (__o, __len); \
397 (void) 0; })
399 # define obstack_alloc(OBSTACK,length) \
400 __extension__ \
401 ({ struct obstack *__h = (OBSTACK); \
402 obstack_blank (__h, (length)); \
403 obstack_finish (__h); })
405 # define obstack_copy(OBSTACK,where,length) \
406 __extension__ \
407 ({ struct obstack *__h = (OBSTACK); \
408 obstack_grow (__h, (where), (length)); \
409 obstack_finish (__h); })
411 # define obstack_copy0(OBSTACK,where,length) \
412 __extension__ \
413 ({ struct obstack *__h = (OBSTACK); \
414 obstack_grow0 (__h, (where), (length)); \
415 obstack_finish (__h); })
417 /* The local variable is named __o1 to avoid a name conflict
418 when obstack_blank is called. */
419 # define obstack_finish(OBSTACK) \
420 __extension__ \
421 ({ struct obstack *__o1 = (OBSTACK); \
422 void *value; \
423 value = (void *) __o1->object_base; \
424 if (__o1->next_free == value) \
425 __o1->maybe_empty_object = 1; \
426 __o1->next_free \
427 = __INT_TO_PTR ((__PTR_TO_INT (__o1->next_free)+__o1->alignment_mask)\
428 & ~ (__o1->alignment_mask)); \
429 if (__o1->next_free - (char *)__o1->chunk \
430 > __o1->chunk_limit - (char *)__o1->chunk) \
431 __o1->next_free = __o1->chunk_limit; \
432 __o1->object_base = __o1->next_free; \
433 value; })
435 # define obstack_free(OBSTACK, OBJ) \
436 __extension__ \
437 ({ struct obstack *__o = (OBSTACK); \
438 void *__obj = (void *) (OBJ); \
439 if (__obj > (void *)__o->chunk && __obj < (void *)__o->chunk_limit) \
440 __o->next_free = __o->object_base = (char *) __obj; \
441 else (obstack_free) (__o, __obj); })
443 #else /* not __GNUC__ or not __STDC__ */
445 # define obstack_object_size(h) \
446 (unsigned) ((h)->next_free - (h)->object_base)
448 # define obstack_room(h) \
449 (unsigned) ((h)->chunk_limit - (h)->next_free)
451 # define obstack_empty_p(h) \
452 ((h)->chunk->prev == 0 && (h)->next_free - (h)->chunk->contents == 0)
454 /* Note that the call to _obstack_newchunk is enclosed in (..., 0)
455 so that we can avoid having void expressions
456 in the arms of the conditional expression.
457 Casting the third operand to void was tried before,
458 but some compilers won't accept it. */
460 # define obstack_make_room(h,length) \
461 ( (h)->temp = (length), \
462 (((h)->next_free + (h)->temp > (h)->chunk_limit) \
463 ? (_obstack_newchunk ((h), (h)->temp), 0) : 0))
465 # define obstack_grow(h,where,length) \
466 ( (h)->temp = (length), \
467 (((h)->next_free + (h)->temp > (h)->chunk_limit) \
468 ? (_obstack_newchunk ((h), (h)->temp), 0) : 0), \
469 _obstack_memcpy ((h)->next_free, (where), (h)->temp), \
470 (h)->next_free += (h)->temp)
472 # define obstack_grow0(h,where,length) \
473 ( (h)->temp = (length), \
474 (((h)->next_free + (h)->temp + 1 > (h)->chunk_limit) \
475 ? (_obstack_newchunk ((h), (h)->temp + 1), 0) : 0), \
476 _obstack_memcpy ((h)->next_free, (where), (h)->temp), \
477 (h)->next_free += (h)->temp, \
478 *((h)->next_free)++ = 0)
480 # define obstack_1grow(h,datum) \
481 ( (((h)->next_free + 1 > (h)->chunk_limit) \
482 ? (_obstack_newchunk ((h), 1), 0) : 0), \
483 obstack_1grow_fast (h, datum))
485 # define obstack_ptr_grow(h,datum) \
486 ( (((h)->next_free + sizeof (char *) > (h)->chunk_limit) \
487 ? (_obstack_newchunk ((h), sizeof (char *)), 0) : 0), \
488 obstack_ptr_grow_fast (h, datum))
490 # define obstack_int_grow(h,datum) \
491 ( (((h)->next_free + sizeof (int) > (h)->chunk_limit) \
492 ? (_obstack_newchunk ((h), sizeof (int)), 0) : 0), \
493 obstack_int_grow_fast (h, datum))
495 # define obstack_ptr_grow_fast(h,aptr) \
496 (((const void **) ((h)->next_free += sizeof (void *)))[-1] = (aptr))
498 # define obstack_int_grow_fast(h,aint) \
499 (((int *) ((h)->next_free += sizeof (int)))[-1] = (aptr))
501 # define obstack_blank(h,length) \
502 ( (h)->temp = (length), \
503 (((h)->chunk_limit - (h)->next_free < (h)->temp) \
504 ? (_obstack_newchunk ((h), (h)->temp), 0) : 0), \
505 obstack_blank_fast (h, (h)->temp))
507 # define obstack_alloc(h,length) \
508 (obstack_blank ((h), (length)), obstack_finish ((h)))
510 # define obstack_copy(h,where,length) \
511 (obstack_grow ((h), (where), (length)), obstack_finish ((h)))
513 # define obstack_copy0(h,where,length) \
514 (obstack_grow0 ((h), (where), (length)), obstack_finish ((h)))
516 # define obstack_finish(h) \
517 ( ((h)->next_free == (h)->object_base \
518 ? (((h)->maybe_empty_object = 1), 0) \
519 : 0), \
520 (h)->temp = __PTR_TO_INT ((h)->object_base), \
521 (h)->next_free \
522 = __INT_TO_PTR ((__PTR_TO_INT ((h)->next_free)+(h)->alignment_mask) \
523 & ~ ((h)->alignment_mask)), \
524 (((h)->next_free - (char *) (h)->chunk \
525 > (h)->chunk_limit - (char *) (h)->chunk) \
526 ? ((h)->next_free = (h)->chunk_limit) : 0), \
527 (h)->object_base = (h)->next_free, \
528 (void *) __INT_TO_PTR ((h)->temp))
530 # define obstack_free(h,obj) \
531 ( (h)->temp = (char *) (obj) - (char *) (h)->chunk, \
532 (((h)->temp > 0 && (h)->temp < (h)->chunk_limit - (char *) (h)->chunk)\
533 ? (((h)->next_free = (h)->object_base \
534 = (h)->temp + (char *) (h)->chunk), 0) \
535 : ((obstack_free) ((h), (h)->temp + (char *) (h)->chunk), 0)))
537 #endif /* not __GNUC__ or not __STDC__ */
539 #ifdef __cplusplus
540 } /* C++ */
541 #endif
543 #endif /* obstack.h */