gcc/vec.c

   1 /* Vector API for GNU compiler.
   2    Copyright (C) 2004, 2005, 2006, 2007, 2008, 2010, 2011, 2012
   3    Free Software Foundation, Inc.
   4    Contributed by Nathan Sidwell <nathan@codesourcery.com>
   5    Re-implemented in C++ by Diego Novillo <dnovillo@google.com>
   6
   7 This file is part of GCC.
   8
   9 GCC is free software; you can redistribute it and/or modify it under
  10 the terms of the GNU General Public License as published by the Free
  11 Software Foundation; either version 3, or (at your option) any later
  12 version.
  13
  14 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  15 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  16 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  17 for more details.
  18
  19 You should have received a copy of the GNU General Public License
  20 along with GCC; see the file COPYING3.  If not see
  21 <http://www.gnu.org/licenses/>.  */
  22
  23 /* This file is compiled twice: once for the generator programs
  24    once for the compiler.  */
  25 #ifdef GENERATOR_FILE
  26 #include "bconfig.h"
  27 #else
  28 #include "config.h"
  29 #endif
  30
  31 #include "system.h"
  32 #include "coretypes.h"
  33 #include "ggc.h"
  34 #include "vec.h"
  35 #include "diagnostic-core.h"
  36 #include "hashtab.h"
  37
  38 /* Store information about each particular vector.  */
  39 struct vec_descriptor
  40 {
  41   const char *function;
  42   const char *file;
  43   int line;
  44   size_t allocated;
  45   size_t times;
  46   size_t peak;
  47 };
  48
  49
  50 /* Hashtable mapping vec addresses to descriptors.  */
  51 static htab_t vec_desc_hash;
  52
  53 /* Hashtable helpers.  */
  54 static hashval_t
  55 hash_descriptor (const void *p)
  56 {
  57   const struct vec_descriptor *const d =
  58     (const struct vec_descriptor *) p;
  59   return htab_hash_pointer (d->file) + d->line;
  60 }
  61 static int
  62 eq_descriptor (const void *p1, const void *p2)
  63 {
  64   const struct vec_descriptor *const d = (const struct vec_descriptor *) p1;
  65   const struct vec_descriptor *const l = (const struct vec_descriptor *) p2;
  66   return d->file == l->file && d->function == l->function && d->line == l->line;
  67 }
  68
  69 /* Hashtable converting address of allocated field to loc descriptor.  */
  70 static htab_t ptr_hash;
  71 struct ptr_hash_entry
  72 {
  73   void *ptr;
  74   struct vec_descriptor *loc;
  75   size_t allocated;
  76 };
  77
  78 /* Hash table helpers functions.  */
  79 static hashval_t
  80 hash_ptr (const void *p)
  81 {
  82   const struct ptr_hash_entry *const d = (const struct ptr_hash_entry *) p;
  83
  84   return htab_hash_pointer (d->ptr);
  85 }
  86
  87 static int
  88 eq_ptr (const void *p1, const void *p2)
  89 {
  90   const struct ptr_hash_entry *const p = (const struct ptr_hash_entry *) p1;
  91
  92   return (p->ptr == p2);
  93 }
  94
  95 /* Return descriptor for given call site, create new one if needed.  */
  96 static struct vec_descriptor *
  97 vec_descriptor (const char *name, int line, const char *function)
  98 {
  99   struct vec_descriptor loc;
 100   struct vec_descriptor **slot;
 101
 102   loc.file = name;
 103   loc.line = line;
 104   loc.function = function;
 105   if (!vec_desc_hash)
 106     vec_desc_hash = htab_create (10, hash_descriptor, eq_descriptor, NULL);
 107
 108   slot = (struct vec_descriptor **) htab_find_slot (vec_desc_hash, &loc,
 109                                                     INSERT);
 110   if (*slot)
 111     return *slot;
 112   *slot = XCNEW (struct vec_descriptor);
 113   (*slot)->file = name;
 114   (*slot)->line = line;
 115   (*slot)->function = function;
 116   (*slot)->allocated = 0;
 117   (*slot)->peak = 0;
 118   return *slot;
 119 }
 120
 121 /* Account the overhead.  */
 122 static void
 123 register_overhead (struct vec_prefix *ptr, size_t size,
 124                    const char *name, int line, const char *function)
 125 {
 126   struct vec_descriptor *loc = vec_descriptor (name, line, function);
 127   struct ptr_hash_entry *p = XNEW (struct ptr_hash_entry);
 128   PTR *slot;
 129
 130   p->ptr = ptr;
 131   p->loc = loc;
 132   p->allocated = size;
 133   if (!ptr_hash)
 134     ptr_hash = htab_create (10, hash_ptr, eq_ptr, NULL);
 135   slot = htab_find_slot_with_hash (ptr_hash, ptr, htab_hash_pointer (ptr), INSERT);
 136   gcc_assert (!*slot);
 137   *slot = p;
 138
 139   loc->allocated += size;
 140   if (loc->peak < loc->allocated)
 141     loc->peak += loc->allocated;
 142   loc->times++;
 143 }
 144
 145 /* Notice that the pointer has been freed.  */
 146 static void
 147 free_overhead (struct vec_prefix *ptr)
 148 {
 149   PTR *slot = htab_find_slot_with_hash (ptr_hash, ptr, htab_hash_pointer (ptr),
 150                                         NO_INSERT);
 151   struct ptr_hash_entry *p = (struct ptr_hash_entry *) *slot;
 152   p->loc->allocated -= p->allocated;
 153   htab_clear_slot (ptr_hash, slot);
 154   free (p);
 155 }
 156
 157 void
 158 vec_heap_free (void *ptr)
 159 {
 160   if (GATHER_STATISTICS)
 161     free_overhead ((struct vec_prefix *)ptr);
 162   free (ptr);
 163 }
 164
 165 /* Calculate the new ALLOC value, making sure that RESERVE slots are
 166    free.  If EXACT grow exactly, otherwise grow exponentially.  */
 167
 168 static inline unsigned
 169 calculate_allocation (const struct vec_prefix *pfx, int reserve, bool exact)
 170 {
 171   unsigned alloc = 0;
 172   unsigned num = 0;
 173
 174   gcc_assert (reserve >= 0);
 175
 176   if (pfx)
 177     {
 178       alloc = pfx->alloc_;
 179       num = pfx->num_;
 180     }
 181   else if (!reserve)
 182     /* If there's no prefix, and we've not requested anything, then we
 183        will create a NULL vector.  */
 184     return 0;
 185
 186   /* We must have run out of room.  */
 187   gcc_assert (alloc - num < (unsigned) reserve);
 188
 189   if (exact)
 190     /* Exact size.  */
 191     alloc = num + reserve;
 192   else
 193     {
 194       /* Exponential growth. */
 195       if (!alloc)
 196         alloc = 4;
 197       else if (alloc < 16)
 198         /* Double when small.  */
 199         alloc = alloc * 2;
 200       else
 201         /* Grow slower when large.  */
 202         alloc = (alloc * 3 / 2);
 203
 204       /* If this is still too small, set it to the right size. */
 205       if (alloc < num + reserve)
 206         alloc = num + reserve;
 207     }
 208   return alloc;
 209 }
 210
 211 /* Ensure there are at least RESERVE free slots in VEC.  If EXACT grow
 212    exactly, else grow exponentially.  As a special case, if VEC is
 213    NULL and RESERVE is 0, no vector will be created.  The vector's
 214    trailing array is at VEC_OFFSET offset and consists of ELT_SIZE
 215    sized elements.  */
 216
 217 void *
 218 vec_gc_o_reserve_1 (void *vec, int reserve, size_t vec_offset, size_t elt_size,
 219                     bool exact MEM_STAT_DECL)
 220 {
 221   struct vec_prefix *pfx = (struct vec_prefix *) vec;
 222   unsigned alloc = calculate_allocation (pfx, reserve, exact);
 223   size_t size;
 224
 225   if (!alloc)
 226     {
 227       if (pfx)
 228         ggc_free (pfx);
 229       return NULL;
 230     }
 231
 232   /* Calculate the amount of space we want.  */
 233   size = vec_offset + alloc * elt_size;
 234   /* Ask the allocator how much space it will really give us.  */
 235   size = ggc_round_alloc_size (size);
 236   /* Adjust the number of slots accordingly.  */
 237   alloc = (size - vec_offset) / elt_size;
 238   /* And finally, recalculate the amount of space we ask for.  */
 239   size = vec_offset + alloc * elt_size;
 240
 241   vec = ggc_realloc_stat (vec, size PASS_MEM_STAT);
 242
 243   ((struct vec_prefix *)vec)->alloc_ = alloc;
 244   if (!pfx)
 245     ((struct vec_prefix *)vec)->num_ = 0;
 246
 247   return vec;
 248 }
 249
 250
 251 /* As for vec_gc_o_reserve_1, but for heap allocated vectors.  */
 252
 253 void *
 254 vec_heap_o_reserve_1 (void *vec, int reserve, size_t vec_offset,
 255                       size_t elt_size, bool exact MEM_STAT_DECL)
 256 {
 257   struct vec_prefix *pfx = (struct vec_prefix *) vec;
 258   unsigned alloc = calculate_allocation (pfx, reserve, exact);
 259
 260   if (!alloc)
 261     {
 262       if (pfx)
 263         vec_heap_free (pfx);
 264       return NULL;
 265     }
 266
 267   if (GATHER_STATISTICS && vec)
 268     free_overhead (pfx);
 269
 270   vec = xrealloc (vec, vec_offset + alloc * elt_size);
 271   ((struct vec_prefix *)vec)->alloc_ = alloc;
 272   if (!pfx)
 273     ((struct vec_prefix *)vec)->num_ = 0;
 274   if (GATHER_STATISTICS && vec)
 275     register_overhead ((struct vec_prefix *)vec,
 276                        vec_offset + alloc * elt_size FINAL_PASS_MEM_STAT);
 277
 278   return vec;
 279 }
 280
 281
 282 /* Stack vectors are a little different.  VEC_alloc turns into a call
 283    to vec_stack_p_reserve_exact1 and passes in space allocated via a
 284    call to alloca.  We record that pointer so that we know that we
 285    shouldn't free it.  If the vector is resized, we resize it on the
 286    heap.  We record the pointers in a vector and search it in LIFO
 287    order--i.e., we look for the newest stack vectors first.  We don't
 288    expect too many stack vectors at any one level, and searching from
 289    the end should normally be efficient even if they are used in a
 290    recursive function.  */
 291
 292 typedef void *void_p;
 293 DEF_VEC_P(void_p);
 294 DEF_VEC_ALLOC_P(void_p,heap);
 295
 296 static VEC(void_p,heap) *stack_vecs;
 297
 298 /* Allocate a vector which uses alloca for the initial allocation.
 299    SPACE is space allocated using alloca, ALLOC is the number of
 300    entries allocated.  */
 301
 302 void *
 303 vec_stack_p_reserve_exact_1 (int alloc, void *space)
 304 {
 305   struct vec_prefix *pfx = (struct vec_prefix *) space;
 306
 307   VEC_safe_push (void_p, heap, stack_vecs, space);
 308
 309   pfx->num_ = 0;
 310   pfx->alloc_ = alloc;
 311
 312   return space;
 313 }
 314
 315 /* Grow a vector allocated using alloca.  When this happens, we switch
 316    back to heap allocation.  We remove the vector from stack_vecs, if
 317    it is there, since we no longer need to avoid freeing it.  */
 318
 319 static void *
 320 vec_stack_o_reserve_1 (void *vec, int reserve, size_t vec_offset,
 321                        size_t elt_size, bool exact MEM_STAT_DECL)
 322 {
 323   bool found;
 324   unsigned int ix;
 325   void *newvec;
 326
 327   found = false;
 328   for (ix = VEC_length (void_p, stack_vecs); ix > 0; --ix)
 329     {
 330       if (VEC_index (void_p, stack_vecs, ix - 1) == vec)
 331         {
 332           VEC_unordered_remove (void_p, stack_vecs, ix - 1);
 333           found = true;
 334           break;
 335         }
 336     }
 337
 338   if (!found)
 339     {
 340       /* VEC is already on the heap.  */
 341       return vec_heap_o_reserve_1 (vec, reserve, vec_offset, elt_size,
 342                                    exact PASS_MEM_STAT);
 343     }
 344
 345   /* Move VEC to the heap.  */
 346   reserve += ((struct vec_prefix *) vec)->num_;
 347   newvec = vec_heap_o_reserve_1 (NULL, reserve, vec_offset, elt_size,
 348                                  exact PASS_MEM_STAT);
 349   if (newvec && vec)
 350     {
 351       ((struct vec_prefix *) newvec)->num_ = ((struct vec_prefix *) vec)->num_;
 352       memcpy (((struct vec_prefix *) newvec)+1,
 353               ((struct vec_prefix *) vec)+1,
 354               ((struct vec_prefix *) vec)->num_ * elt_size);
 355     }
 356   return newvec;
 357 }
 358
 359 /* Grow a vector allocated on the stack.  */
 360
 361 void *
 362 vec_stack_o_reserve (void *vec, int reserve, size_t vec_offset,
 363                      size_t elt_size MEM_STAT_DECL)
 364 {
 365   return vec_stack_o_reserve_1 (vec, reserve, vec_offset, elt_size, false
 366                                 PASS_MEM_STAT);
 367 }
 368
 369 /* Exact version of vec_stack_o_reserve.  */
 370
 371 void *
 372 vec_stack_o_reserve_exact (void *vec, int reserve, size_t vec_offset,
 373                             size_t elt_size MEM_STAT_DECL)
 374 {
 375   return vec_stack_o_reserve_1 (vec, reserve, vec_offset, elt_size, true
 376                                 PASS_MEM_STAT);
 377 }
 378
 379 /* Free a vector allocated on the stack.  Don't actually free it if we
 380    find it in the hash table.  */
 381
 382 void
 383 vec_stack_free (void *vec)
 384 {
 385   unsigned int ix;
 386
 387   for (ix = VEC_length (void_p, stack_vecs); ix > 0; --ix)
 388     {
 389       if (VEC_index (void_p, stack_vecs, ix - 1) == vec)
 390         {
 391           VEC_unordered_remove (void_p, stack_vecs, ix - 1);
 392           return;
 393         }
 394     }
 395
 396   /* VEC was not on the list of vecs allocated on the stack, so it
 397      must be allocated on the heap.  */
 398   vec_heap_free (vec);
 399 }
 400
 401 #if ENABLE_CHECKING
 402 /* Issue a vector domain error, and then fall over.  */
 403
 404 void
 405 vec_assert_fail (const char *op, const char *struct_name,
 406                  const char *file, unsigned int line, const char *function)
 407 {
 408   internal_error ("vector %s %s domain error, in %s at %s:%u",
 409                   struct_name, op, function, trim_filename (file), line);
 410 }
 411 #endif
 412
 413 /* Helper for qsort; sort descriptors by amount of memory consumed.  */
 414 static int
 415 cmp_statistic (const void *loc1, const void *loc2)
 416 {
 417   const struct vec_descriptor *const l1 =
 418     *(const struct vec_descriptor *const *) loc1;
 419   const struct vec_descriptor *const l2 =
 420     *(const struct vec_descriptor *const *) loc2;
 421   long diff;
 422   diff = l1->allocated - l2->allocated;
 423   if (!diff)
 424     diff = l1->peak - l2->peak;
 425   if (!diff)
 426     diff = l1->times - l2->times;
 427   return diff > 0 ? 1 : diff < 0 ? -1 : 0;
 428 }
 429 /* Collect array of the descriptors from hashtable.  */
 430 static struct vec_descriptor **loc_array;
 431 static int
 432 add_statistics (void **slot, void *b)
 433 {
 434   int *n = (int *)b;
 435   loc_array[*n] = (struct vec_descriptor *) *slot;
 436   (*n)++;
 437   return 1;
 438 }
 439
 440 /* Dump per-site memory statistics.  */
 441
 442 void
 443 dump_vec_loc_statistics (void)
 444 {
 445   int nentries = 0;
 446   char s[4096];
 447   size_t allocated = 0;
 448   size_t times = 0;
 449   int i;
 450
 451   if (! GATHER_STATISTICS)
 452     return;
 453
 454   loc_array = XCNEWVEC (struct vec_descriptor *, vec_desc_hash->n_elements);
 455   fprintf (stderr, "Heap vectors:\n");
 456   fprintf (stderr, "\n%-48s %10s       %10s       %10s\n",
 457            "source location", "Leak", "Peak", "Times");
 458   fprintf (stderr, "-------------------------------------------------------\n");
 459   htab_traverse (vec_desc_hash, add_statistics, &nentries);
 460   qsort (loc_array, nentries, sizeof (*loc_array), cmp_statistic);
 461   for (i = 0; i < nentries; i++)
 462     {
 463       struct vec_descriptor *d = loc_array[i];
 464       allocated += d->allocated;
 465       times += d->times;
 466     }
 467   for (i = 0; i < nentries; i++)
 468     {
 469       struct vec_descriptor *d = loc_array[i];
 470       const char *s1 = d->file;
 471       const char *s2;
 472       while ((s2 = strstr (s1, "gcc/")))
 473         s1 = s2 + 4;
 474       sprintf (s, "%s:%i (%s)", s1, d->line, d->function);
 475       s[48] = 0;
 476       fprintf (stderr, "%-48s %10li:%4.1f%% %10li      %10li:%4.1f%% \n", s,
 477                (long)d->allocated,
 478                (d->allocated) * 100.0 / allocated,
 479                (long)d->peak,
 480                (long)d->times,
 481                (d->times) * 100.0 / times);
 482     }
 483   fprintf (stderr, "%-48s %10ld                        %10ld\n",
 484            "Total", (long)allocated, (long)times);
 485   fprintf (stderr, "\n%-48s %10s       %10s       %10s\n",
 486            "source location", "Leak", "Peak", "Times");
 487   fprintf (stderr, "-------------------------------------------------------\n");
 488 }