boehm-gc/malloc.c

   1 /*
   2  * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
   3  * Copyright (c) 1991-1994 by Xerox Corporation.  All rights reserved.
   4  * Copyright (c) 2000 by Hewlett-Packard Company.  All rights reserved.
   5  *
   6  * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
   7  * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
   8  *
   9  * Permission is hereby granted to use or copy this program
  10  * for any purpose,  provided the above notices are retained on all copies.
  11  * Permission to modify the code and to distribute modified code is granted,
  12  * provided the above notices are retained, and a notice that the code was
  13  * modified is included with the above copyright notice.
  14  */
  15 /* Boehm, February 7, 1996 4:32 pm PST */
  16
  17 #include <stdio.h>
  18 #include "private/gc_priv.h"
  19
  20 extern ptr_t GC_clear_stack();  /* in misc.c, behaves like identity */
  21 void GC_extend_size_map();      /* in misc.c. */
  22
  23 /* Allocate reclaim list for kind:      */
  24 /* Return TRUE on success               */
  25 GC_bool GC_alloc_reclaim_list(kind)
  26 register struct obj_kind * kind;
  27 {
  28     struct hblk ** result = (struct hblk **)
  29                 GC_scratch_alloc((MAXOBJSZ+1) * sizeof(struct hblk *));
  30     if (result == 0) return(FALSE);
  31     BZERO(result, (MAXOBJSZ+1)*sizeof(struct hblk *));
  32     kind -> ok_reclaim_list = result;
  33     return(TRUE);
  34 }
  35
  36 /* Allocate a large block of size lw words.     */
  37 /* The block is not cleared.                    */
  38 /* Flags is 0 or IGNORE_OFF_PAGE.               */
  39 ptr_t GC_alloc_large(lw, k, flags)
  40 word lw;
  41 int k;
  42 unsigned flags;
  43 {
  44     struct hblk * h;
  45     word n_blocks = OBJ_SZ_TO_BLOCKS(lw);
  46     ptr_t result;
  47
  48     if (!GC_is_initialized) GC_init_inner();
  49     /* Do our share of marking work */
  50         if(GC_incremental && !GC_dont_gc)
  51             GC_collect_a_little_inner((int)n_blocks);
  52     h = GC_allochblk(lw, k, flags);
  53 #   ifdef USE_MUNMAP
  54         if (0 == h) {
  55             GC_merge_unmapped();
  56             h = GC_allochblk(lw, k, flags);
  57         }
  58 #   endif
  59     while (0 == h && GC_collect_or_expand(n_blocks, (flags != 0))) {
  60         h = GC_allochblk(lw, k, flags);
  61     }
  62     if (h == 0) {
  63         result = 0;
  64     } else {
  65         int total_bytes = BYTES_TO_WORDS(n_blocks * HBLKSIZE);
  66         if (n_blocks > 1) {
  67             GC_large_allocd_bytes += n_blocks * HBLKSIZE;
  68             if (GC_large_allocd_bytes > GC_max_large_allocd_bytes)
  69                 GC_max_large_allocd_bytes = GC_large_allocd_bytes;
  70         }
  71         result = (ptr_t) (h -> hb_body);
  72         GC_words_wasted += total_bytes - lw;
  73     }
  74     return result;
  75 }
  76
  77
  78 /* Allocate a large block of size lb bytes.  Clear if appropriate.      */
  79 ptr_t GC_alloc_large_and_clear(lw, k, flags)
  80 word lw;
  81 int k;
  82 unsigned flags;
  83 {
  84     ptr_t result = GC_alloc_large(lw, k, flags);
  85     word n_blocks = OBJ_SZ_TO_BLOCKS(lw);
  86
  87     if (0 == result) return 0;
  88     if (GC_debugging_started || GC_obj_kinds[k].ok_init) {
  89         /* Clear the whole block, in case of GC_realloc call. */
  90         BZERO(result, n_blocks * HBLKSIZE);
  91     }
  92     return result;
  93 }
  94
  95 /* allocate lb bytes for an object of kind k.   */
  96 /* Should not be used to directly to allocate   */
  97 /* objects such as STUBBORN objects that        */
  98 /* require special handling on allocation.      */
  99 /* First a version that assumes we already      */
 100 /* hold lock:                                   */
 101 ptr_t GC_generic_malloc_inner(lb, k)
 102 register word lb;
 103 register int k;
 104 {
 105 register word lw;
 106 register ptr_t op;
 107 register ptr_t *opp;
 108
 109     if( SMALL_OBJ(lb) ) {
 110         register struct obj_kind * kind = GC_obj_kinds + k;
 111 #       ifdef MERGE_SIZES
 112           lw = GC_size_map[lb];
 113 #       else
 114           lw = ALIGNED_WORDS(lb);
 115           if (lw == 0) lw = MIN_WORDS;
 116 #       endif
 117         opp = &(kind -> ok_freelist[lw]);
 118         if( (op = *opp) == 0 ) {
 119 #           ifdef MERGE_SIZES
 120               if (GC_size_map[lb] == 0) {
 121                 if (!GC_is_initialized)  GC_init_inner();
 122                 if (GC_size_map[lb] == 0) GC_extend_size_map(lb);
 123                 return(GC_generic_malloc_inner(lb, k));
 124               }
 125 #           else
 126               if (!GC_is_initialized) {
 127                 GC_init_inner();
 128                 return(GC_generic_malloc_inner(lb, k));
 129               }
 130 #           endif
 131             if (kind -> ok_reclaim_list == 0) {
 132                 if (!GC_alloc_reclaim_list(kind)) goto out;
 133             }
 134             op = GC_allocobj(lw, k);
 135             if (op == 0) goto out;
 136         }
 137         /* Here everything is in a consistent state.    */
 138         /* We assume the following assignment is        */
 139         /* atomic.  If we get aborted                   */
 140         /* after the assignment, we lose an object,     */
 141         /* but that's benign.                           */
 142         /* Volatile declarations may need to be added   */
 143         /* to prevent the compiler from breaking things.*/
 144         /* If we only execute the second of the         */
 145         /* following assignments, we lose the free      */
 146         /* list, but that should still be OK, at least  */
 147         /* for garbage collected memory.                */
 148         *opp = obj_link(op);
 149         obj_link(op) = 0;
 150     } else {
 151         lw = ROUNDED_UP_WORDS(lb);
 152         op = (ptr_t)GC_alloc_large_and_clear(lw, k, 0);
 153     }
 154     GC_words_allocd += lw;
 155
 156 out:
 157     return op;
 158 }
 159
 160 /* Allocate a composite object of size n bytes.  The caller guarantees  */
 161 /* that pointers past the first page are not relevant.  Caller holds    */
 162 /* allocation lock.                                                     */
 163 ptr_t GC_generic_malloc_inner_ignore_off_page(lb, k)
 164 register size_t lb;
 165 register int k;
 166 {
 167     register word lw;
 168     ptr_t op;
 169
 170     if (lb <= HBLKSIZE)
 171         return(GC_generic_malloc_inner((word)lb, k));
 172     lw = ROUNDED_UP_WORDS(lb);
 173     op = (ptr_t)GC_alloc_large_and_clear(lw, k, IGNORE_OFF_PAGE);
 174     GC_words_allocd += lw;
 175     return op;
 176 }
 177
 178 ptr_t GC_generic_malloc(lb, k)
 179 register word lb;
 180 register int k;
 181 {
 182     ptr_t result;
 183     DCL_LOCK_STATE;
 184
 185     GC_INVOKE_FINALIZERS();
 186     if (SMALL_OBJ(lb)) {
 187         DISABLE_SIGNALS();
 188         LOCK();
 189         result = GC_generic_malloc_inner((word)lb, k);
 190         UNLOCK();
 191         ENABLE_SIGNALS();
 192     } else {
 193         word lw;
 194         word n_blocks;
 195         GC_bool init;
 196         lw = ROUNDED_UP_WORDS(lb);
 197         n_blocks = OBJ_SZ_TO_BLOCKS(lw);
 198         init = GC_obj_kinds[k].ok_init;
 199         DISABLE_SIGNALS();
 200         LOCK();
 201         result = (ptr_t)GC_alloc_large(lw, k, 0);
 202         if (0 != result) {
 203           if (GC_debugging_started) {
 204             BZERO(result, n_blocks * HBLKSIZE);
 205           } else {
 206 #           ifdef THREADS
 207               /* Clear any memory that might be used for GC descriptors */
 208               /* before we release the lock.                          */
 209                 ((word *)result)[0] = 0;
 210                 ((word *)result)[1] = 0;
 211                 ((word *)result)[lw-1] = 0;
 212                 ((word *)result)[lw-2] = 0;
 213 #           endif
 214           }
 215         }
 216         GC_words_allocd += lw;
 217         UNLOCK();
 218         ENABLE_SIGNALS();
 219         if (init & !GC_debugging_started && 0 != result) {
 220             BZERO(result, n_blocks * HBLKSIZE);
 221         }
 222     }
 223     if (0 == result) {
 224         return((*GC_oom_fn)(lb));
 225     } else {
 226         return(result);
 227     }
 228 }
 229
 230
 231 #define GENERAL_MALLOC(lb,k) \
 232     (GC_PTR)GC_clear_stack(GC_generic_malloc((word)lb, k))
 233 /* We make the GC_clear_stack_call a tail call, hoping to get more of   */
 234 /* the stack.                                                           */
 235
 236 /* Allocate lb bytes of atomic (pointerfree) data */
 237 # ifdef __STDC__
 238     GC_PTR GC_malloc_atomic(size_t lb)
 239 # else
 240     GC_PTR GC_malloc_atomic(lb)
 241     size_t lb;
 242 # endif
 243 {
 244 register ptr_t op;
 245 register ptr_t * opp;
 246 register word lw;
 247 DCL_LOCK_STATE;
 248
 249     if( EXPECT(SMALL_OBJ(lb), 1) ) {
 250 #       ifdef MERGE_SIZES
 251           lw = GC_size_map[lb];
 252 #       else
 253           lw = ALIGNED_WORDS(lb);
 254 #       endif
 255         opp = &(GC_aobjfreelist[lw]);
 256         FASTLOCK();
 257         if( EXPECT(!FASTLOCK_SUCCEEDED() || (op = *opp) == 0, 0) ) {
 258             FASTUNLOCK();
 259             return(GENERAL_MALLOC((word)lb, PTRFREE));
 260         }
 261         /* See above comment on signals.        */
 262         *opp = obj_link(op);
 263         GC_words_allocd += lw;
 264         FASTUNLOCK();
 265         return((GC_PTR) op);
 266    } else {
 267        return(GENERAL_MALLOC((word)lb, PTRFREE));
 268    }
 269 }
 270
 271 /* Allocate lb bytes of composite (pointerful) data */
 272 # ifdef __STDC__
 273     GC_PTR GC_malloc(size_t lb)
 274 # else
 275     GC_PTR GC_malloc(lb)
 276     size_t lb;
 277 # endif
 278 {
 279 register ptr_t op;
 280 register ptr_t *opp;
 281 register word lw;
 282 DCL_LOCK_STATE;
 283
 284     if( EXPECT(SMALL_OBJ(lb), 1) ) {
 285 #       ifdef MERGE_SIZES
 286           lw = GC_size_map[lb];
 287 #       else
 288           lw = ALIGNED_WORDS(lb);
 289 #       endif
 290         opp = &(GC_objfreelist[lw]);
 291         FASTLOCK();
 292         if( EXPECT(!FASTLOCK_SUCCEEDED() || (op = *opp) == 0, 0) ) {
 293             FASTUNLOCK();
 294             return(GENERAL_MALLOC((word)lb, NORMAL));
 295         }
 296         /* See above comment on signals.        */
 297         *opp = obj_link(op);
 298         obj_link(op) = 0;
 299         GC_words_allocd += lw;
 300         FASTUNLOCK();
 301         return((GC_PTR) op);
 302    } else {
 303        return(GENERAL_MALLOC((word)lb, NORMAL));
 304    }
 305 }
 306
 307 # ifdef REDIRECT_MALLOC
 308 # ifdef __STDC__
 309     GC_PTR malloc(size_t lb)
 310 # else
 311     GC_PTR malloc(lb)
 312     size_t lb;
 313 # endif
 314   {
 315     /* It might help to manually inline the GC_malloc call here.        */
 316     /* But any decent compiler should reduce the extra procedure call   */
 317     /* to at most a jump instruction in this case.                      */
 318 #   if defined(I386) && defined(GC_SOLARIS_THREADS)
 319       /*
 320        * Thread initialisation can call malloc before
 321        * we're ready for it.
 322        * It's not clear that this is enough to help matters.
 323        * The thread implementation may well call malloc at other
 324        * inopportune times.
 325        */
 326       if (!GC_is_initialized) return sbrk(lb);
 327 #   endif /* I386 && GC_SOLARIS_THREADS */
 328     return((GC_PTR)REDIRECT_MALLOC(lb));
 329   }
 330
 331 # ifdef __STDC__
 332     GC_PTR calloc(size_t n, size_t lb)
 333 # else
 334     GC_PTR calloc(n, lb)
 335     size_t n, lb;
 336 # endif
 337   {
 338     return((GC_PTR)REDIRECT_MALLOC(n*lb));
 339   }
 340 # endif /* REDIRECT_MALLOC */
 341
 342 /* Explicitly deallocate an object p.                           */
 343 # ifdef __STDC__
 344     void GC_free(GC_PTR p)
 345 # else
 346     void GC_free(p)
 347     GC_PTR p;
 348 # endif
 349 {
 350     register struct hblk *h;
 351     register hdr *hhdr;
 352     register signed_word sz;
 353     register ptr_t * flh;
 354     register int knd;
 355     register struct obj_kind * ok;
 356     DCL_LOCK_STATE;
 357
 358     if (p == 0) return;
 359         /* Required by ANSI.  It's not my fault ...     */
 360     h = HBLKPTR(p);
 361     hhdr = HDR(h);
 362 #   if defined(REDIRECT_MALLOC) && \
 363         (defined(GC_SOLARIS_THREADS) || defined(GC_LINUX_THREADS) \
 364          || defined(__MINGW32__)) /* Should this be MSWIN32 in general? */
 365         /* For Solaris, we have to redirect malloc calls during         */
 366         /* initialization.  For the others, this seems to happen        */
 367         /* implicitly.                                                  */
 368         /* Don't try to deallocate that memory.                         */
 369         if (0 == hhdr) return;
 370 #   endif
 371     knd = hhdr -> hb_obj_kind;
 372     sz = hhdr -> hb_sz;
 373     ok = &GC_obj_kinds[knd];
 374     if (EXPECT((sz <= MAXOBJSZ), 1)) {
 375 #       ifdef THREADS
 376             DISABLE_SIGNALS();
 377             LOCK();
 378 #       endif
 379         GC_mem_freed += sz;
 380         /* A signal here can make GC_mem_freed and GC_non_gc_bytes      */
 381         /* inconsistent.  We claim this is benign.                      */
 382         if (IS_UNCOLLECTABLE(knd)) GC_non_gc_bytes -= WORDS_TO_BYTES(sz);
 383                 /* Its unnecessary to clear the mark bit.  If the       */
 384                 /* object is reallocated, it doesn't matter.  O.w. the  */
 385                 /* collector will do it, since it's on a free list.     */
 386         if (ok -> ok_init) {
 387             BZERO((word *)p + 1, WORDS_TO_BYTES(sz-1));
 388         }
 389         flh = &(ok -> ok_freelist[sz]);
 390         obj_link(p) = *flh;
 391         *flh = (ptr_t)p;
 392 #       ifdef THREADS
 393             UNLOCK();
 394             ENABLE_SIGNALS();
 395 #       endif
 396     } else {
 397         DISABLE_SIGNALS();
 398         LOCK();
 399         GC_mem_freed += sz;
 400         if (IS_UNCOLLECTABLE(knd)) GC_non_gc_bytes -= WORDS_TO_BYTES(sz);
 401         GC_freehblk(h);
 402         UNLOCK();
 403         ENABLE_SIGNALS();
 404     }
 405 }
 406
 407 /* Explicitly deallocate an object p when we already hold lock.         */
 408 /* Only used for internally allocated objects, so we can take some      */
 409 /* shortcuts.                                                           */
 410 #ifdef THREADS
 411 void GC_free_inner(GC_PTR p)
 412 {
 413     register struct hblk *h;
 414     register hdr *hhdr;
 415     register signed_word sz;
 416     register ptr_t * flh;
 417     register int knd;
 418     register struct obj_kind * ok;
 419     DCL_LOCK_STATE;
 420
 421     h = HBLKPTR(p);
 422     hhdr = HDR(h);
 423     knd = hhdr -> hb_obj_kind;
 424     sz = hhdr -> hb_sz;
 425     ok = &GC_obj_kinds[knd];
 426     if (sz <= MAXOBJSZ) {
 427         GC_mem_freed += sz;
 428         if (IS_UNCOLLECTABLE(knd)) GC_non_gc_bytes -= WORDS_TO_BYTES(sz);
 429         if (ok -> ok_init) {
 430             BZERO((word *)p + 1, WORDS_TO_BYTES(sz-1));
 431         }
 432         flh = &(ok -> ok_freelist[sz]);
 433         obj_link(p) = *flh;
 434         *flh = (ptr_t)p;
 435     } else {
 436         GC_mem_freed += sz;
 437         if (IS_UNCOLLECTABLE(knd)) GC_non_gc_bytes -= WORDS_TO_BYTES(sz);
 438         GC_freehblk(h);
 439     }
 440 }
 441 #endif /* THREADS */
 442
 443 # ifdef REDIRECT_MALLOC
 444 #   ifdef __STDC__
 445       void free(GC_PTR p)
 446 #   else
 447       void free(p)
 448       GC_PTR p;
 449 #   endif
 450   {
 451 #   ifndef IGNORE_FREE
 452       GC_free(p);
 453 #   endif
 454   }
 455 # endif  /* REDIRECT_MALLOC */