gcc/ggc-common.c

   1 /* Simple garbage collection for the GNU compiler.
   2    Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004, 2005
   3    Free Software Foundation, Inc.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 2, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING.  If not, write to the Free
  19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  20 02111-1307, USA.  */
  21
  22 /* Generic garbage collection (GC) functions and data, not specific to
  23    any particular GC implementation.  */
  24
  25 #include "config.h"
  26 #include "system.h"
  27 #include "coretypes.h"
  28 #include "hashtab.h"
  29 #include "ggc.h"
  30 #include "toplev.h"
  31 #include "params.h"
  32 #include "hosthooks.h"
  33 #include "hosthooks-def.h"
  34
  35 #ifdef HAVE_SYS_RESOURCE_H
  36 # include <sys/resource.h>
  37 #endif
  38
  39 #ifdef HAVE_MMAP_FILE
  40 # include <sys/mman.h>
  41 # ifdef HAVE_MINCORE
  42 /* This is on Solaris.  */
  43 #  include <sys/types.h>
  44 # endif
  45 #endif
  46
  47 #ifndef MAP_FAILED
  48 # define MAP_FAILED ((void *)-1)
  49 #endif
  50
  51 #ifdef ENABLE_VALGRIND_CHECKING
  52 # ifdef HAVE_VALGRIND_MEMCHECK_H
  53 #  include <valgrind/memcheck.h>
  54 # elif defined HAVE_MEMCHECK_H
  55 #  include <memcheck.h>
  56 # else
  57 #  include <valgrind.h>
  58 # endif
  59 #else
  60 /* Avoid #ifdef:s when we can help it.  */
  61 #define VALGRIND_DISCARD(x)
  62 #endif
  63
  64 /* When set, ggc_collect will do collection.  */
  65 bool ggc_force_collect;
  66
  67 /* Statistics about the allocation.  */
  68 static ggc_statistics *ggc_stats;
  69
  70 struct traversal_state;
  71
  72 static int ggc_htab_delete (void **, void *);
  73 static hashval_t saving_htab_hash (const void *);
  74 static int saving_htab_eq (const void *, const void *);
  75 static int call_count (void **, void *);
  76 static int call_alloc (void **, void *);
  77 static int compare_ptr_data (const void *, const void *);
  78 static void relocate_ptrs (void *, void *);
  79 static void write_pch_globals (const struct ggc_root_tab * const *tab,
  80                                struct traversal_state *state);
  81 static double ggc_rlimit_bound (double);
  82
  83 /* Maintain global roots that are preserved during GC.  */
  84
  85 /* Process a slot of an htab by deleting it if it has not been marked.  */
  86
  87 static int
  88 ggc_htab_delete (void **slot, void *info)
  89 {
  90   const struct ggc_cache_tab *r = (const struct ggc_cache_tab *) info;
  91
  92   if (! (*r->marked_p) (*slot))
  93     htab_clear_slot (*r->base, slot);
  94   else
  95     (*r->cb) (*slot);
  96
  97   return 1;
  98 }
  99
 100 /* Iterate through all registered roots and mark each element.  */
 101
 102 void
 103 ggc_mark_roots (void)
 104 {
 105   const struct ggc_root_tab *const *rt;
 106   const struct ggc_root_tab *rti;
 107   const struct ggc_cache_tab *const *ct;
 108   const struct ggc_cache_tab *cti;
 109   size_t i;
 110
 111   for (rt = gt_ggc_deletable_rtab; *rt; rt++)
 112     for (rti = *rt; rti->base != NULL; rti++)
 113       memset (rti->base, 0, rti->stride);
 114
 115   for (rt = gt_ggc_rtab; *rt; rt++)
 116     for (rti = *rt; rti->base != NULL; rti++)
 117       for (i = 0; i < rti->nelt; i++)
 118         (*rti->cb)(*(void **)((char *)rti->base + rti->stride * i));
 119
 120   ggc_mark_stringpool ();
 121
 122   /* Now scan all hash tables that have objects which are to be deleted if
 123      they are not already marked.  */
 124   for (ct = gt_ggc_cache_rtab; *ct; ct++)
 125     for (cti = *ct; cti->base != NULL; cti++)
 126       if (*cti->base)
 127         {
 128           ggc_set_mark (*cti->base);
 129           htab_traverse_noresize (*cti->base, ggc_htab_delete, (void *) cti);
 130           ggc_set_mark ((*cti->base)->entries);
 131         }
 132 }
 133
 134 /* Allocate a block of memory, then clear it.  */
 135 void *
 136 ggc_alloc_cleared_stat (size_t size MEM_STAT_DECL)
 137 {
 138   void *buf = ggc_alloc_stat (size PASS_MEM_STAT);
 139   memset (buf, 0, size);
 140   return buf;
 141 }
 142
 143 /* Resize a block of memory, possibly re-allocating it.  */
 144 void *
 145 ggc_realloc_stat (void *x, size_t size MEM_STAT_DECL)
 146 {
 147   void *r;
 148   size_t old_size;
 149
 150   if (x == NULL)
 151     return ggc_alloc_stat (size PASS_MEM_STAT);
 152
 153   old_size = ggc_get_size (x);
 154
 155   if (size <= old_size)
 156     {
 157       /* Mark the unwanted memory as unaccessible.  We also need to make
 158          the "new" size accessible, since ggc_get_size returns the size of
 159          the pool, not the size of the individually allocated object, the
 160          size which was previously made accessible.  Unfortunately, we
 161          don't know that previously allocated size.  Without that
 162          knowledge we have to lose some initialization-tracking for the
 163          old parts of the object.  An alternative is to mark the whole
 164          old_size as reachable, but that would lose tracking of writes
 165          after the end of the object (by small offsets).  Discard the
 166          handle to avoid handle leak.  */
 167       VALGRIND_DISCARD (VALGRIND_MAKE_NOACCESS ((char *) x + size,
 168                                                 old_size - size));
 169       VALGRIND_DISCARD (VALGRIND_MAKE_READABLE (x, size));
 170       return x;
 171     }
 172
 173   r = ggc_alloc_stat (size PASS_MEM_STAT);
 174
 175   /* Since ggc_get_size returns the size of the pool, not the size of the
 176      individually allocated object, we'd access parts of the old object
 177      that were marked invalid with the memcpy below.  We lose a bit of the
 178      initialization-tracking since some of it may be uninitialized.  */
 179   VALGRIND_DISCARD (VALGRIND_MAKE_READABLE (x, old_size));
 180
 181   memcpy (r, x, old_size);
 182
 183   /* The old object is not supposed to be used anymore.  */
 184   ggc_free (x);
 185
 186   return r;
 187 }
 188
 189 /* Like ggc_alloc_cleared, but performs a multiplication.  */
 190 void *
 191 ggc_calloc (size_t s1, size_t s2)
 192 {
 193   return ggc_alloc_cleared (s1 * s2);
 194 }
 195
 196 /* These are for splay_tree_new_ggc.  */
 197 void *
 198 ggc_splay_alloc (int sz, void *nl)
 199 {
 200   gcc_assert (!nl);
 201   return ggc_alloc (sz);
 202 }
 203
 204 void
 205 ggc_splay_dont_free (void * x ATTRIBUTE_UNUSED, void *nl)
 206 {
 207   gcc_assert (!nl);
 208 }
 209
 210 /* Print statistics that are independent of the collector in use.  */
 211 #define SCALE(x) ((unsigned long) ((x) < 1024*10 \
 212                   ? (x) \
 213                   : ((x) < 1024*1024*10 \
 214                      ? (x) / 1024 \
 215                      : (x) / (1024*1024))))
 216 #define LABEL(x) ((x) < 1024*10 ? ' ' : ((x) < 1024*1024*10 ? 'k' : 'M'))
 217
 218 void
 219 ggc_print_common_statistics (FILE *stream ATTRIBUTE_UNUSED,
 220                              ggc_statistics *stats)
 221 {
 222   /* Set the pointer so that during collection we will actually gather
 223      the statistics.  */
 224   ggc_stats = stats;
 225
 226   /* Then do one collection to fill in the statistics.  */
 227   ggc_collect ();
 228
 229   /* At present, we don't really gather any interesting statistics.  */
 230
 231   /* Don't gather statistics any more.  */
 232   ggc_stats = NULL;
 233 }
 234 \f
 235 /* Functions for saving and restoring GCable memory to disk.  */
 236
 237 static htab_t saving_htab;
 238
 239 struct ptr_data
 240 {
 241   void *obj;
 242   void *note_ptr_cookie;
 243   gt_note_pointers note_ptr_fn;
 244   gt_handle_reorder reorder_fn;
 245   size_t size;
 246   void *new_addr;
 247   enum gt_types_enum type;
 248 };
 249
 250 #define POINTER_HASH(x) (hashval_t)((long)x >> 3)
 251
 252 /* Register an object in the hash table.  */
 253
 254 int
 255 gt_pch_note_object (void *obj, void *note_ptr_cookie,
 256                     gt_note_pointers note_ptr_fn,
 257                     enum gt_types_enum type)
 258 {
 259   struct ptr_data **slot;
 260
 261   if (obj == NULL || obj == (void *) 1)
 262     return 0;
 263
 264   slot = (struct ptr_data **)
 265     htab_find_slot_with_hash (saving_htab, obj, POINTER_HASH (obj),
 266                               INSERT);
 267   if (*slot != NULL)
 268     {
 269       gcc_assert ((*slot)->note_ptr_fn == note_ptr_fn
 270                   && (*slot)->note_ptr_cookie == note_ptr_cookie);
 271       return 0;
 272     }
 273
 274   *slot = xcalloc (sizeof (struct ptr_data), 1);
 275   (*slot)->obj = obj;
 276   (*slot)->note_ptr_fn = note_ptr_fn;
 277   (*slot)->note_ptr_cookie = note_ptr_cookie;
 278   if (note_ptr_fn == gt_pch_p_S)
 279     (*slot)->size = strlen (obj) + 1;
 280   else
 281     (*slot)->size = ggc_get_size (obj);
 282   (*slot)->type = type;
 283   return 1;
 284 }
 285
 286 /* Register an object in the hash table.  */
 287
 288 void
 289 gt_pch_note_reorder (void *obj, void *note_ptr_cookie,
 290                      gt_handle_reorder reorder_fn)
 291 {
 292   struct ptr_data *data;
 293
 294   if (obj == NULL || obj == (void *) 1)
 295     return;
 296
 297   data = htab_find_with_hash (saving_htab, obj, POINTER_HASH (obj));
 298   gcc_assert (data && data->note_ptr_cookie == note_ptr_cookie);
 299
 300   data->reorder_fn = reorder_fn;
 301 }
 302
 303 /* Hash and equality functions for saving_htab, callbacks for htab_create.  */
 304
 305 static hashval_t
 306 saving_htab_hash (const void *p)
 307 {
 308   return POINTER_HASH (((struct ptr_data *)p)->obj);
 309 }
 310
 311 static int
 312 saving_htab_eq (const void *p1, const void *p2)
 313 {
 314   return ((struct ptr_data *)p1)->obj == p2;
 315 }
 316
 317 /* Handy state for the traversal functions.  */
 318
 319 struct traversal_state
 320 {
 321   FILE *f;
 322   struct ggc_pch_data *d;
 323   size_t count;
 324   struct ptr_data **ptrs;
 325   size_t ptrs_i;
 326 };
 327
 328 /* Callbacks for htab_traverse.  */
 329
 330 static int
 331 call_count (void **slot, void *state_p)
 332 {
 333   struct ptr_data *d = (struct ptr_data *)*slot;
 334   struct traversal_state *state = (struct traversal_state *)state_p;
 335
 336   ggc_pch_count_object (state->d, d->obj, d->size,
 337                         d->note_ptr_fn == gt_pch_p_S,
 338                         d->type);
 339   state->count++;
 340   return 1;
 341 }
 342
 343 static int
 344 call_alloc (void **slot, void *state_p)
 345 {
 346   struct ptr_data *d = (struct ptr_data *)*slot;
 347   struct traversal_state *state = (struct traversal_state *)state_p;
 348
 349   d->new_addr = ggc_pch_alloc_object (state->d, d->obj, d->size,
 350                                       d->note_ptr_fn == gt_pch_p_S,
 351                                       d->type);
 352   state->ptrs[state->ptrs_i++] = d;
 353   return 1;
 354 }
 355
 356 /* Callback for qsort.  */
 357
 358 static int
 359 compare_ptr_data (const void *p1_p, const void *p2_p)
 360 {
 361   struct ptr_data *p1 = *(struct ptr_data *const *)p1_p;
 362   struct ptr_data *p2 = *(struct ptr_data *const *)p2_p;
 363   return (((size_t)p1->new_addr > (size_t)p2->new_addr)
 364           - ((size_t)p1->new_addr < (size_t)p2->new_addr));
 365 }
 366
 367 /* Callbacks for note_ptr_fn.  */
 368
 369 static void
 370 relocate_ptrs (void *ptr_p, void *state_p)
 371 {
 372   void **ptr = (void **)ptr_p;
 373   struct traversal_state *state ATTRIBUTE_UNUSED
 374     = (struct traversal_state *)state_p;
 375   struct ptr_data *result;
 376
 377   if (*ptr == NULL || *ptr == (void *)1)
 378     return;
 379
 380   result = htab_find_with_hash (saving_htab, *ptr, POINTER_HASH (*ptr));
 381   gcc_assert (result);
 382   *ptr = result->new_addr;
 383 }
 384
 385 /* Write out, after relocation, the pointers in TAB.  */
 386 static void
 387 write_pch_globals (const struct ggc_root_tab * const *tab,
 388                    struct traversal_state *state)
 389 {
 390   const struct ggc_root_tab *const *rt;
 391   const struct ggc_root_tab *rti;
 392   size_t i;
 393
 394   for (rt = tab; *rt; rt++)
 395     for (rti = *rt; rti->base != NULL; rti++)
 396       for (i = 0; i < rti->nelt; i++)
 397         {
 398           void *ptr = *(void **)((char *)rti->base + rti->stride * i);
 399           struct ptr_data *new_ptr;
 400           if (ptr == NULL || ptr == (void *)1)
 401             {
 402               if (fwrite (&ptr, sizeof (void *), 1, state->f)
 403                   != 1)
 404                 fatal_error ("can't write PCH file: %m");
 405             }
 406           else
 407             {
 408               new_ptr = htab_find_with_hash (saving_htab, ptr,
 409                                              POINTER_HASH (ptr));
 410               if (fwrite (&new_ptr->new_addr, sizeof (void *), 1, state->f)
 411                   != 1)
 412                 fatal_error ("can't write PCH file: %m");
 413             }
 414         }
 415 }
 416
 417 /* Hold the information we need to mmap the file back in.  */
 418
 419 struct mmap_info
 420 {
 421   size_t offset;
 422   size_t size;
 423   void *preferred_base;
 424 };
 425
 426 /* Write out the state of the compiler to F.  */
 427
 428 void
 429 gt_pch_save (FILE *f)
 430 {
 431   const struct ggc_root_tab *const *rt;
 432   const struct ggc_root_tab *rti;
 433   size_t i;
 434   struct traversal_state state;
 435   char *this_object = NULL;
 436   size_t this_object_size = 0;
 437   struct mmap_info mmi;
 438   const size_t mmap_offset_alignment = host_hooks.gt_pch_alloc_granularity();
 439
 440   gt_pch_save_stringpool ();
 441
 442   saving_htab = htab_create (50000, saving_htab_hash, saving_htab_eq, free);
 443
 444   for (rt = gt_ggc_rtab; *rt; rt++)
 445     for (rti = *rt; rti->base != NULL; rti++)
 446       for (i = 0; i < rti->nelt; i++)
 447         (*rti->pchw)(*(void **)((char *)rti->base + rti->stride * i));
 448
 449   for (rt = gt_pch_cache_rtab; *rt; rt++)
 450     for (rti = *rt; rti->base != NULL; rti++)
 451       for (i = 0; i < rti->nelt; i++)
 452         (*rti->pchw)(*(void **)((char *)rti->base + rti->stride * i));
 453
 454   /* Prepare the objects for writing, determine addresses and such.  */
 455   state.f = f;
 456   state.d = init_ggc_pch();
 457   state.count = 0;
 458   htab_traverse (saving_htab, call_count, &state);
 459
 460   mmi.size = ggc_pch_total_size (state.d);
 461
 462   /* Try to arrange things so that no relocation is necessary, but
 463      don't try very hard.  On most platforms, this will always work,
 464      and on the rest it's a lot of work to do better.
 465      (The extra work goes in HOST_HOOKS_GT_PCH_GET_ADDRESS and
 466      HOST_HOOKS_GT_PCH_USE_ADDRESS.)  */
 467   mmi.preferred_base = host_hooks.gt_pch_get_address (mmi.size, fileno (f));
 468
 469   ggc_pch_this_base (state.d, mmi.preferred_base);
 470
 471   state.ptrs = xmalloc (state.count * sizeof (*state.ptrs));
 472   state.ptrs_i = 0;
 473   htab_traverse (saving_htab, call_alloc, &state);
 474   qsort (state.ptrs, state.count, sizeof (*state.ptrs), compare_ptr_data);
 475
 476   /* Write out all the scalar variables.  */
 477   for (rt = gt_pch_scalar_rtab; *rt; rt++)
 478     for (rti = *rt; rti->base != NULL; rti++)
 479       if (fwrite (rti->base, rti->stride, 1, f) != 1)
 480         fatal_error ("can't write PCH file: %m");
 481
 482   /* Write out all the global pointers, after translation.  */
 483   write_pch_globals (gt_ggc_rtab, &state);
 484   write_pch_globals (gt_pch_cache_rtab, &state);
 485
 486   /* Pad the PCH file so that the mmapped area starts on an allocation
 487      granularity (usually page) boundary.  */
 488   {
 489     long o;
 490     o = ftell (state.f) + sizeof (mmi);
 491     if (o == -1)
 492       fatal_error ("can't get position in PCH file: %m");
 493     mmi.offset = mmap_offset_alignment - o % mmap_offset_alignment;
 494     if (mmi.offset == mmap_offset_alignment)
 495       mmi.offset = 0;
 496     mmi.offset += o;
 497   }
 498   if (fwrite (&mmi, sizeof (mmi), 1, state.f) != 1)
 499     fatal_error ("can't write PCH file: %m");
 500   if (mmi.offset != 0
 501       && fseek (state.f, mmi.offset, SEEK_SET) != 0)
 502     fatal_error ("can't write padding to PCH file: %m");
 503
 504   ggc_pch_prepare_write (state.d, state.f);
 505
 506   /* Actually write out the objects.  */
 507   for (i = 0; i < state.count; i++)
 508     {
 509       if (this_object_size < state.ptrs[i]->size)
 510         {
 511           this_object_size = state.ptrs[i]->size;
 512           this_object = xrealloc (this_object, this_object_size);
 513         }
 514       memcpy (this_object, state.ptrs[i]->obj, state.ptrs[i]->size);
 515       if (state.ptrs[i]->reorder_fn != NULL)
 516         state.ptrs[i]->reorder_fn (state.ptrs[i]->obj,
 517                                    state.ptrs[i]->note_ptr_cookie,
 518                                    relocate_ptrs, &state);
 519       state.ptrs[i]->note_ptr_fn (state.ptrs[i]->obj,
 520                                   state.ptrs[i]->note_ptr_cookie,
 521                                   relocate_ptrs, &state);
 522       ggc_pch_write_object (state.d, state.f, state.ptrs[i]->obj,
 523                             state.ptrs[i]->new_addr, state.ptrs[i]->size,
 524                             state.ptrs[i]->note_ptr_fn == gt_pch_p_S);
 525       if (state.ptrs[i]->note_ptr_fn != gt_pch_p_S)
 526         memcpy (state.ptrs[i]->obj, this_object, state.ptrs[i]->size);
 527     }
 528   ggc_pch_finish (state.d, state.f);
 529   gt_pch_fixup_stringpool ();
 530
 531   free (state.ptrs);
 532   htab_delete (saving_htab);
 533 }
 534
 535 /* Read the state of the compiler back in from F.  */
 536
 537 void
 538 gt_pch_restore (FILE *f)
 539 {
 540   const struct ggc_root_tab *const *rt;
 541   const struct ggc_root_tab *rti;
 542   size_t i;
 543   struct mmap_info mmi;
 544   int result;
 545
 546   /* Delete any deletable objects.  This makes ggc_pch_read much
 547      faster, as it can be sure that no GCable objects remain other
 548      than the ones just read in.  */
 549   for (rt = gt_ggc_deletable_rtab; *rt; rt++)
 550     for (rti = *rt; rti->base != NULL; rti++)
 551       memset (rti->base, 0, rti->stride);
 552
 553   /* Read in all the scalar variables.  */
 554   for (rt = gt_pch_scalar_rtab; *rt; rt++)
 555     for (rti = *rt; rti->base != NULL; rti++)
 556       if (fread (rti->base, rti->stride, 1, f) != 1)
 557         fatal_error ("can't read PCH file: %m");
 558
 559   /* Read in all the global pointers, in 6 easy loops.  */
 560   for (rt = gt_ggc_rtab; *rt; rt++)
 561     for (rti = *rt; rti->base != NULL; rti++)
 562       for (i = 0; i < rti->nelt; i++)
 563         if (fread ((char *)rti->base + rti->stride * i,
 564                    sizeof (void *), 1, f) != 1)
 565           fatal_error ("can't read PCH file: %m");
 566
 567   for (rt = gt_pch_cache_rtab; *rt; rt++)
 568     for (rti = *rt; rti->base != NULL; rti++)
 569       for (i = 0; i < rti->nelt; i++)
 570         if (fread ((char *)rti->base + rti->stride * i,
 571                    sizeof (void *), 1, f) != 1)
 572           fatal_error ("can't read PCH file: %m");
 573
 574   if (fread (&mmi, sizeof (mmi), 1, f) != 1)
 575     fatal_error ("can't read PCH file: %m");
 576
 577   result = host_hooks.gt_pch_use_address (mmi.preferred_base, mmi.size,
 578                                           fileno (f), mmi.offset);
 579   if (result < 0)
 580     fatal_error ("had to relocate PCH");
 581   if (result == 0)
 582     {
 583       if (fseek (f, mmi.offset, SEEK_SET) != 0
 584           || fread (mmi.preferred_base, mmi.size, 1, f) != 1)
 585         fatal_error ("can't read PCH file: %m");
 586     }
 587   else if (fseek (f, mmi.offset + mmi.size, SEEK_SET) != 0)
 588     fatal_error ("can't read PCH file: %m");
 589
 590   ggc_pch_read (f, mmi.preferred_base);
 591
 592   gt_pch_restore_stringpool ();
 593 }
 594
 595 /* Default version of HOST_HOOKS_GT_PCH_GET_ADDRESS when mmap is not present.
 596    Select no address whatsoever, and let gt_pch_save choose what it will with
 597    malloc, presumably.  */
 598
 599 void *
 600 default_gt_pch_get_address (size_t size ATTRIBUTE_UNUSED,
 601                             int fd ATTRIBUTE_UNUSED)
 602 {
 603   return NULL;
 604 }
 605
 606 /* Default version of HOST_HOOKS_GT_PCH_USE_ADDRESS when mmap is not present.
 607    Allocate SIZE bytes with malloc.  Return 0 if the address we got is the
 608    same as base, indicating that the memory has been allocated but needs to
 609    be read in from the file.  Return -1 if the address differs, to relocation
 610    of the PCH file would be required.  */
 611
 612 int
 613 default_gt_pch_use_address (void *base, size_t size, int fd ATTRIBUTE_UNUSED,
 614                             size_t offset ATTRIBUTE_UNUSED)
 615 {
 616   void *addr = xmalloc (size);
 617   return (addr == base) - 1;
 618 }
 619
 620 /* Default version of HOST_HOOKS_GT_PCH_GET_ADDRESS.   Return the
 621    alignment required for allocating virtual memory. Usually this is the
 622    same as pagesize.  */
 623
 624 size_t
 625 default_gt_pch_alloc_granularity (void)
 626 {
 627   return getpagesize();
 628 }
 629
 630 #if HAVE_MMAP_FILE
 631 /* Default version of HOST_HOOKS_GT_PCH_GET_ADDRESS when mmap is present.
 632    We temporarily allocate SIZE bytes, and let the kernel place the data
 633    wherever it will.  If it worked, that's our spot, if not we're likely
 634    to be in trouble.  */
 635
 636 void *
 637 mmap_gt_pch_get_address (size_t size, int fd)
 638 {
 639   void *ret;
 640
 641   ret = mmap (NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
 642   if (ret == (void *) MAP_FAILED)
 643     ret = NULL;
 644   else
 645     munmap (ret, size);
 646
 647   return ret;
 648 }
 649
 650 /* Default version of HOST_HOOKS_GT_PCH_USE_ADDRESS when mmap is present.
 651    Map SIZE bytes of FD+OFFSET at BASE.  Return 1 if we succeeded at
 652    mapping the data at BASE, -1 if we couldn't.
 653
 654    This version assumes that the kernel honors the START operand of mmap
 655    even without MAP_FIXED if START through START+SIZE are not currently
 656    mapped with something.  */
 657
 658 int
 659 mmap_gt_pch_use_address (void *base, size_t size, int fd, size_t offset)
 660 {
 661   void *addr;
 662
 663   /* We're called with size == 0 if we're not planning to load a PCH
 664      file at all.  This allows the hook to free any static space that
 665      we might have allocated at link time.  */
 666   if (size == 0)
 667     return -1;
 668
 669   addr = mmap (base, size, PROT_READ | PROT_WRITE, MAP_PRIVATE,
 670                fd, offset);
 671
 672   return addr == base ? 1 : -1;
 673 }
 674 #endif /* HAVE_MMAP_FILE */
 675
 676 /* Modify the bound based on rlimits.  */
 677 static double
 678 ggc_rlimit_bound (double limit)
 679 {
 680 #if defined(HAVE_GETRLIMIT)
 681   struct rlimit rlim;
 682 # if defined (RLIMIT_AS)
 683   /* RLIMIT_AS is what POSIX says is the limit on mmap.  Presumably
 684      any OS which has RLIMIT_AS also has a working mmap that GCC will use.  */
 685   if (getrlimit (RLIMIT_AS, &rlim) == 0
 686       && rlim.rlim_cur != (rlim_t) RLIM_INFINITY
 687       && rlim.rlim_cur < limit)
 688     limit = rlim.rlim_cur;
 689 # elif defined (RLIMIT_DATA)
 690   /* ... but some older OSs bound mmap based on RLIMIT_DATA, or we
 691      might be on an OS that has a broken mmap.  (Others don't bound
 692      mmap at all, apparently.)  */
 693   if (getrlimit (RLIMIT_DATA, &rlim) == 0
 694       && rlim.rlim_cur != (rlim_t) RLIM_INFINITY
 695       && rlim.rlim_cur < limit
 696       /* Darwin has this horribly bogus default setting of
 697          RLIMIT_DATA, to 6144Kb.  No-one notices because RLIMIT_DATA
 698          appears to be ignored.  Ignore such silliness.  If a limit
 699          this small was actually effective for mmap, GCC wouldn't even
 700          start up.  */
 701       && rlim.rlim_cur >= 8 * 1024 * 1024)
 702     limit = rlim.rlim_cur;
 703 # endif /* RLIMIT_AS or RLIMIT_DATA */
 704 #endif /* HAVE_GETRLIMIT */
 705
 706   return limit;
 707 }
 708
 709 /* Heuristic to set a default for GGC_MIN_EXPAND.  */
 710 int
 711 ggc_min_expand_heuristic (void)
 712 {
 713   double min_expand = physmem_total();
 714
 715   /* Adjust for rlimits.  */
 716   min_expand = ggc_rlimit_bound (min_expand);
 717
 718   /* The heuristic is a percentage equal to 30% + 70%*(RAM/1GB), yielding
 719      a lower bound of 30% and an upper bound of 100% (when RAM >= 1GB).  */
 720   min_expand /= 1024*1024*1024;
 721   min_expand *= 70;
 722   min_expand = MIN (min_expand, 70);
 723   min_expand += 30;
 724
 725   return min_expand;
 726 }
 727
 728 /* Heuristic to set a default for GGC_MIN_HEAPSIZE.  */
 729 int
 730 ggc_min_heapsize_heuristic (void)
 731 {
 732   double phys_kbytes = physmem_total();
 733   double limit_kbytes = ggc_rlimit_bound (phys_kbytes * 2);
 734
 735   phys_kbytes /= 1024; /* Convert to Kbytes.  */
 736   limit_kbytes /= 1024;
 737
 738   /* The heuristic is RAM/8, with a lower bound of 4M and an upper
 739      bound of 128M (when RAM >= 1GB).  */
 740   phys_kbytes /= 8;
 741
 742 #if defined(HAVE_GETRLIMIT) && defined (RLIMIT_RSS)
 743   /* Try not to overrun the RSS limit while doing garbage collection.
 744      The RSS limit is only advisory, so no margin is subtracted.  */
 745  {
 746    struct rlimit rlim;
 747    if (getrlimit (RLIMIT_RSS, &rlim) == 0
 748        && rlim.rlim_cur != (rlim_t) RLIM_INFINITY)
 749      phys_kbytes = MIN (phys_kbytes, rlim.rlim_cur / 1024);
 750  }
 751 # endif
 752
 753   /* Don't blindly run over our data limit; do GC at least when the
 754      *next* GC would be within 16Mb of the limit.  If GCC does hit the
 755      data limit, compilation will fail, so this tries to be
 756      conservative.  */
 757   limit_kbytes = MAX (0, limit_kbytes - 16 * 1024);
 758   limit_kbytes = (limit_kbytes * 100) / (110 + ggc_min_expand_heuristic());
 759   phys_kbytes = MIN (phys_kbytes, limit_kbytes);
 760
 761   phys_kbytes = MAX (phys_kbytes, 4 * 1024);
 762   phys_kbytes = MIN (phys_kbytes, 128 * 1024);
 763
 764   return phys_kbytes;
 765 }
 766
 767 void
 768 init_ggc_heuristics (void)
 769 {
 770 #if !defined ENABLE_GC_CHECKING && !defined ENABLE_GC_ALWAYS_COLLECT
 771   set_param_value ("ggc-min-expand", ggc_min_expand_heuristic());
 772   set_param_value ("ggc-min-heapsize", ggc_min_heapsize_heuristic());
 773 #endif
 774 }
 775
 776 #ifdef GATHER_STATISTICS
 777
 778 /* Datastructure used to store per-call-site statistics.  */
 779 struct loc_descriptor
 780 {
 781   const char *file;
 782   int line;
 783   const char *function;
 784   int times;
 785   size_t allocated;
 786   size_t overhead;
 787   size_t freed;
 788   size_t collected;
 789 };
 790
 791 /* Hashtable used for statistics.  */
 792 static htab_t loc_hash;
 793
 794 /* Hash table helpers functions.  */
 795 static hashval_t
 796 hash_descriptor (const void *p)
 797 {
 798   const struct loc_descriptor *d = p;
 799
 800   return htab_hash_pointer (d->function) | d->line;
 801 }
 802
 803 static int
 804 eq_descriptor (const void *p1, const void *p2)
 805 {
 806   const struct loc_descriptor *d = p1;
 807   const struct loc_descriptor *d2 = p2;
 808
 809   return (d->file == d2->file && d->line == d2->line
 810           && d->function == d2->function);
 811 }
 812
 813 /* Hashtable converting address of allocated field to loc descriptor.  */
 814 static htab_t ptr_hash;
 815 struct ptr_hash_entry
 816 {
 817   void *ptr;
 818   struct loc_descriptor *loc;
 819   size_t size;
 820 };
 821
 822 /* Hash table helpers functions.  */
 823 static hashval_t
 824 hash_ptr (const void *p)
 825 {
 826   const struct ptr_hash_entry *d = p;
 827
 828   return htab_hash_pointer (d->ptr);
 829 }
 830
 831 static int
 832 eq_ptr (const void *p1, const void *p2)
 833 {
 834   const struct ptr_hash_entry *p = p1;
 835
 836   return (p->ptr == p2);
 837 }
 838
 839 /* Return descriptor for given call site, create new one if needed.  */
 840 static struct loc_descriptor *
 841 loc_descriptor (const char *name, int line, const char *function)
 842 {
 843   struct loc_descriptor loc;
 844   struct loc_descriptor **slot;
 845
 846   loc.file = name;
 847   loc.line = line;
 848   loc.function = function;
 849   if (!loc_hash)
 850     loc_hash = htab_create (10, hash_descriptor, eq_descriptor, NULL);
 851
 852   slot = (struct loc_descriptor **) htab_find_slot (loc_hash, &loc, 1);
 853   if (*slot)
 854     return *slot;
 855   *slot = xcalloc (sizeof (**slot), 1);
 856   (*slot)->file = name;
 857   (*slot)->line = line;
 858   (*slot)->function = function;
 859   return *slot;
 860 }
 861
 862 /* Record ALLOCATED and OVERHEAD bytes to descriptor NAME:LINE (FUNCTION).  */
 863 void
 864 ggc_record_overhead (size_t allocated, size_t overhead, void *ptr,
 865                      const char *name, int line, const char *function)
 866 {
 867   struct loc_descriptor *loc = loc_descriptor (name, line, function);
 868   struct ptr_hash_entry *p = xmalloc (sizeof (struct ptr_hash_entry));
 869   PTR *slot;
 870
 871   p->ptr = ptr;
 872   p->loc = loc;
 873   p->size = allocated + overhead;
 874   if (!ptr_hash)
 875     ptr_hash = htab_create (10, hash_ptr, eq_ptr, NULL);
 876   slot = htab_find_slot_with_hash (ptr_hash, ptr, htab_hash_pointer (ptr), INSERT);
 877   gcc_assert (!*slot);
 878   *slot = p;
 879
 880   loc->times++;
 881   loc->allocated+=allocated;
 882   loc->overhead+=overhead;
 883 }
 884
 885 /* Helper function for prune_overhead_list.  See if SLOT is still marked and
 886    remove it from hashtable if it is not.  */
 887 static int
 888 ggc_prune_ptr (void **slot, void *b ATTRIBUTE_UNUSED)
 889 {
 890   struct ptr_hash_entry *p = *slot;
 891   if (!ggc_marked_p (p->ptr))
 892     {
 893       p->loc->collected += p->size;
 894       htab_clear_slot (ptr_hash, slot);
 895       free (p);
 896     }
 897   return 1;
 898 }
 899
 900 /* After live values has been marked, walk all recorded pointers and see if
 901    they are still live.  */
 902 void
 903 ggc_prune_overhead_list (void)
 904 {
 905   htab_traverse (ptr_hash, ggc_prune_ptr, NULL);
 906 }
 907
 908 /* Notice that the pointer has been freed.  */
 909 void ggc_free_overhead (void *ptr)
 910 {
 911   PTR *slot = htab_find_slot_with_hash (ptr_hash, ptr, htab_hash_pointer (ptr),
 912                                         NO_INSERT);
 913   struct ptr_hash_entry *p = *slot;
 914   p->loc->freed += p->size;
 915   htab_clear_slot (ptr_hash, slot);
 916   free (p);
 917 }
 918
 919 /* Helper for qsort; sort descriptors by amount of memory consumed.  */
 920 static int
 921 cmp_statistic (const void *loc1, const void *loc2)
 922 {
 923   struct loc_descriptor *l1 = *(struct loc_descriptor **) loc1;
 924   struct loc_descriptor *l2 = *(struct loc_descriptor **) loc2;
 925   return ((l1->allocated + l1->overhead - l1->freed) -
 926           (l2->allocated + l2->overhead - l2->freed));
 927 }
 928
 929 /* Collect array of the descriptors from hashtable.  */
 930 struct loc_descriptor **loc_array;
 931 static int
 932 add_statistics (void **slot, void *b)
 933 {
 934   int *n = (int *)b;
 935   loc_array[*n] = (struct loc_descriptor *) *slot;
 936   (*n)++;
 937   return 1;
 938 }
 939
 940 /* Dump per-site memory statistics.  */
 941 #endif
 942 void dump_ggc_loc_statistics (void)
 943 {
 944 #ifdef GATHER_STATISTICS
 945   int nentries = 0;
 946   char s[4096];
 947   size_t collected = 0, freed = 0, allocated = 0, overhead = 0, times = 0;
 948   int i;
 949
 950   ggc_force_collect = true;
 951   ggc_collect ();
 952
 953   loc_array = xcalloc (sizeof (*loc_array), loc_hash->n_elements);
 954   fprintf (stderr, "-------------------------------------------------------\n");
 955   fprintf (stderr, "\n%-48s %10s       %10s       %10s       %10s       %10s\n",
 956            "source location", "Garbage", "Freed", "Leak", "Overhead", "Times");
 957   fprintf (stderr, "-------------------------------------------------------\n");
 958   htab_traverse (loc_hash, add_statistics, &nentries);
 959   qsort (loc_array, nentries, sizeof (*loc_array), cmp_statistic);
 960   for (i = 0; i < nentries; i++)
 961     {
 962       struct loc_descriptor *d = loc_array[i];
 963       allocated += d->allocated;
 964       times += d->times;
 965       freed += d->freed;
 966       collected += d->collected;
 967       overhead += d->overhead;
 968     }
 969   for (i = 0; i < nentries; i++)
 970     {
 971       struct loc_descriptor *d = loc_array[i];
 972       if (d->allocated)
 973         {
 974           const char *s1 = d->file;
 975           const char *s2;
 976           while ((s2 = strstr (s1, "gcc/")))
 977             s1 = s2 + 4;
 978           sprintf (s, "%s:%i (%s)", s1, d->line, d->function);
 979           s[48] = 0;
 980           fprintf (stderr, "%-48s %10li:%4.1f%% %10li:%4.1f%% %10li:%4.1f%% %10li:%4.1f%% %10li\n", s,
 981                    (long)d->collected,
 982                    (d->collected) * 100.0 / collected,
 983                    (long)d->freed,
 984                    (d->freed) * 100.0 / freed,
 985                    (long)(d->allocated + d->overhead - d->freed - d->collected),
 986                    (d->allocated + d->overhead - d->freed - d->collected) * 100.0
 987                    / (allocated + overhead - freed - collected),
 988                    (long)d->overhead,
 989                    d->overhead * 100.0 / overhead,
 990                    (long)d->times);
 991         }
 992     }
 993   fprintf (stderr, "%-48s %10ld       %10ld       %10ld       %10ld       %10ld\n",
 994            "Total", (long)collected, (long)freed,
 995            (long)(allocated + overhead - freed - collected), (long)overhead,
 996            (long)times);
 997   fprintf (stderr, "%-48s %10s       %10s       %10s       %10s       %10s\n",
 998            "source location", "Garbage", "Freed", "Leak", "Overhead", "Times");
 999   fprintf (stderr, "-------------------------------------------------------\n");
1000 #endif
1001 }