1 /* Functions to support a pool of allocatable objects 2 Copyright (C) 1997-2019 Free Software Foundation, Inc. 3 Contributed by Daniel Berlin <dan@cgsoftware.com> 4 5 This file is part of GCC. 6 7 GCC is free software; you can redistribute it and/or modify 8 it under the terms of the GNU General Public License as published by 9 the Free Software Foundation; either version 3, or (at your option) 10 any later version. 11 12 GCC is distributed in the hope that it will be useful, 13 but WITHOUT ANY WARRANTY; without even the implied warranty of 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 GNU General Public License for more details. 16 17 You should have received a copy of the GNU General Public License 18 along with GCC; see the file COPYING3. If not see 19 <http://www.gnu.org/licenses/>. */ 20 #ifndef ALLOC_POOL_H 21 #define ALLOC_POOL_H 22 23 #include "memory-block.h" 24 #include "options.h" // for flag_checking 25 26 extern void dump_alloc_pool_statistics (void); 27 28 /* Flag indicates whether memory statistics are gathered any longer. */ 29 extern bool after_memory_report; 30 31 typedef unsigned long ALLOC_POOL_ID_TYPE; 32 33 /* Last used ID. */ 34 extern ALLOC_POOL_ID_TYPE last_id; 35 36 /* Pool allocator memory usage. */ 37 struct pool_usage: public mem_usage 38 { 39 /* Default contructor. */ 40 pool_usage (): m_element_size (0), m_pool_name ("") {} 41 /* Constructor. */ 42 pool_usage (size_t allocated, size_t times, size_t peak, 43 size_t instances, size_t element_size, 44 const char *pool_name) 45 : mem_usage (allocated, times, peak, instances), 46 m_element_size (element_size), 47 m_pool_name (pool_name) {} 48 49 /* Sum the usage with SECOND usage. */ 50 pool_usage 51 operator+ (const pool_usage &second) 52 { 53 return pool_usage (m_allocated + second.m_allocated, 54 m_times + second.m_times, 55 m_peak + second.m_peak, 56 m_instances + second.m_instances, 57 m_element_size, m_pool_name); 58 } 59 60 /* Dump usage coupled to LOC location, where TOTAL is sum of all rows. */ 61 inline void 62 dump (mem_location *loc, mem_usage &total) const 63 { 64 char *location_string = loc->to_string (); 65 66 fprintf (stderr, "%-32s%-48s " PRsa(5) PRsa(9) ":%5.1f%%" 67 PRsa(9) PRsa(9) ":%5.1f%%%12" PRIu64 "\n", 68 m_pool_name, location_string, 69 SIZE_AMOUNT (m_instances), 70 SIZE_AMOUNT (m_allocated), 71 get_percent (m_allocated, total.m_allocated), 72 SIZE_AMOUNT (m_peak), 73 SIZE_AMOUNT (m_times), 74 get_percent (m_times, total.m_times), 75 (uint64_t)m_element_size); 76 77 free (location_string); 78 } 79 80 /* Dump header with NAME. */ 81 static inline void 82 dump_header (const char *name) 83 { 84 fprintf (stderr, "%-32s%-48s %6s%11s%16s%17s%12s\n", "Pool name", name, 85 "Pools", "Leak", "Peak", "Times", "Elt size"); 86 } 87 88 /* Dump footer. */ 89 inline void 90 dump_footer () 91 { 92 fprintf (stderr, "%s" PRsa(82) PRsa(10) "\n", "Total", 93 SIZE_AMOUNT (m_instances), SIZE_AMOUNT (m_allocated)); 94 } 95 96 /* Element size. */ 97 size_t m_element_size; 98 /* Pool name. */ 99 const char *m_pool_name; 100 }; 101 102 extern mem_alloc_description<pool_usage> pool_allocator_usage; 103 104 #if 0 105 /* If a pool with custom block size is needed, one might use the following 106 template. An instance of this template can be used as a parameter for 107 instantiating base_pool_allocator template: 108 109 typedef custom_block_allocator <128*1024> huge_block_allocator; 110 ... 111 static base_pool_allocator <huge_block_allocator> 112 value_pool ("value", 16384); 113 114 Right now it's not used anywhere in the code, and is given here as an 115 example). */ 116 117 template <size_t BlockSize> 118 class custom_block_allocator 119 { 120 public: 121 static const size_t block_size = BlockSize; 122 123 static inline void * 124 allocate () ATTRIBUTE_MALLOC 125 { 126 return XNEWVEC (char, BlockSize); 127 } 128 129 static inline void 130 release (void *block) 131 { 132 XDELETEVEC (block); 133 } 134 }; 135 #endif 136 137 /* Generic pool allocator. */ 138 139 template <typename TBlockAllocator> 140 class base_pool_allocator 141 { 142 public: 143 /* Default constructor for pool allocator called NAME. */ 144 base_pool_allocator (const char *name, size_t size CXX_MEM_STAT_INFO); 145 ~base_pool_allocator (); 146 void release (); 147 void release_if_empty (); 148 void *allocate () ATTRIBUTE_MALLOC; 149 void remove (void *object); 150 size_t num_elts_current (); 151 152 private: 153 struct allocation_pool_list 154 { 155 allocation_pool_list *next; 156 }; 157 158 /* Initialize a pool allocator. */ 159 void initialize (); 160 161 struct allocation_object 162 { 163 #if CHECKING_P 164 /* The ID of alloc pool which the object was allocated from. */ 165 ALLOC_POOL_ID_TYPE id; 166 #endif 167 168 union 169 { 170 /* The data of the object. */ 171 char data[1]; 172 173 /* Because we want any type of data to be well aligned after the ID, 174 the following elements are here. They are never accessed so 175 the allocated object may be even smaller than this structure. 176 We do not care about alignment for floating-point types. */ 177 char *align_p; 178 int64_t align_i; 179 } u; 180 181 #if CHECKING_P 182 static inline allocation_object* 183 get_instance (void *data_ptr) 184 { 185 return (allocation_object *)(((char *)(data_ptr)) 186 - offsetof (allocation_object, 187 u.data)); 188 } 189 #endif 190 191 static inline void* 192 get_data (void *instance_ptr) 193 { 194 return (void*)(((allocation_object *) instance_ptr)->u.data); 195 } 196 }; 197 198 /* Align X to 8. */ 199 static inline size_t 200 align_eight (size_t x) 201 { 202 return (((x+7) >> 3) << 3); 203 } 204 205 const char *m_name; 206 ALLOC_POOL_ID_TYPE m_id; 207 size_t m_elts_per_block; 208 209 /* These are the elements that have been allocated at least once 210 and freed. */ 211 allocation_pool_list *m_returned_free_list; 212 213 /* These are the elements that have not yet been allocated out of 214 the last block obtained from XNEWVEC. */ 215 char* m_virgin_free_list; 216 217 /* The number of elements in the virgin_free_list that can be 218 allocated before needing another block. */ 219 size_t m_virgin_elts_remaining; 220 /* The number of elements that are allocated. */ 221 size_t m_elts_allocated; 222 /* The number of elements that are released. */ 223 size_t m_elts_free; 224 /* The number of allocated blocks. */ 225 size_t m_blocks_allocated; 226 /* List of blocks that are used to allocate new objects. */ 227 allocation_pool_list *m_block_list; 228 /* Size of a pool elements in bytes. */ 229 size_t m_elt_size; 230 /* Size in bytes that should be allocated for each element. */ 231 size_t m_size; 232 /* Flag if a pool allocator is initialized. */ 233 bool m_initialized; 234 /* Memory allocation location. */ 235 mem_location m_location; 236 }; 237 238 template <typename TBlockAllocator> 239 inline 240 base_pool_allocator <TBlockAllocator>::base_pool_allocator ( 241 const char *name, size_t size MEM_STAT_DECL): 242 m_name (name), m_id (0), m_elts_per_block (0), m_returned_free_list (NULL), 243 m_virgin_free_list (NULL), m_virgin_elts_remaining (0), m_elts_allocated (0), 244 m_elts_free (0), m_blocks_allocated (0), m_block_list (NULL), m_elt_size (0), 245 m_size (size), m_initialized (false), 246 m_location (ALLOC_POOL_ORIGIN, false PASS_MEM_STAT) {} 247 248 /* Initialize a pool allocator. */ 249 250 template <typename TBlockAllocator> 251 inline void 252 base_pool_allocator <TBlockAllocator>::initialize () 253 { 254 gcc_checking_assert (!m_initialized); 255 m_initialized = true; 256 257 size_t size = m_size; 258 259 gcc_checking_assert (m_name); 260 gcc_checking_assert (m_size); 261 262 /* Make size large enough to store the list header. */ 263 if (size < sizeof (allocation_pool_list*)) 264 size = sizeof (allocation_pool_list*); 265 266 /* Now align the size to a multiple of 8. */ 267 size = align_eight (size); 268 269 /* Add the aligned size of ID. */ 270 size += offsetof (allocation_object, u.data); 271 272 m_elt_size = size; 273 274 if (GATHER_STATISTICS) 275 { 276 pool_usage *u = pool_allocator_usage.register_descriptor 277 (this, new mem_location (m_location)); 278 279 u->m_element_size = m_elt_size; 280 u->m_pool_name = m_name; 281 } 282 283 /* List header size should be a multiple of 8. */ 284 size_t header_size = align_eight (sizeof (allocation_pool_list)); 285 286 m_elts_per_block = (TBlockAllocator::block_size - header_size) / size; 287 gcc_checking_assert (m_elts_per_block != 0); 288 289 /* Increase the last used ID and use it for this pool. 290 ID == 0 is used for free elements of pool so skip it. */ 291 last_id++; 292 if (last_id == 0) 293 last_id++; 294 295 m_id = last_id; 296 } 297 298 /* Free all memory allocated for the given memory pool. */ 299 template <typename TBlockAllocator> 300 inline void 301 base_pool_allocator <TBlockAllocator>::release () 302 { 303 if (!m_initialized) 304 return; 305 306 allocation_pool_list *block, *next_block; 307 308 /* Free each block allocated to the pool. */ 309 for (block = m_block_list; block != NULL; block = next_block) 310 { 311 next_block = block->next; 312 TBlockAllocator::release (block); 313 } 314 315 if (GATHER_STATISTICS && !after_memory_report) 316 { 317 pool_allocator_usage.release_instance_overhead 318 (this, (m_elts_allocated - m_elts_free) * m_elt_size); 319 } 320 321 m_returned_free_list = NULL; 322 m_virgin_free_list = NULL; 323 m_virgin_elts_remaining = 0; 324 m_elts_allocated = 0; 325 m_elts_free = 0; 326 m_blocks_allocated = 0; 327 m_block_list = NULL; 328 } 329 330 template <typename TBlockAllocator> 331 inline void 332 base_pool_allocator <TBlockAllocator>::release_if_empty () 333 { 334 if (m_elts_free == m_elts_allocated) 335 release (); 336 } 337 338 template <typename TBlockAllocator> 339 inline base_pool_allocator <TBlockAllocator>::~base_pool_allocator () 340 { 341 release (); 342 } 343 344 /* Allocates one element from the pool specified. */ 345 template <typename TBlockAllocator> 346 inline void* 347 base_pool_allocator <TBlockAllocator>::allocate () 348 { 349 if (!m_initialized) 350 initialize (); 351 352 allocation_pool_list *header; 353 #ifdef ENABLE_VALGRIND_ANNOTATIONS 354 int size; 355 #endif 356 357 if (GATHER_STATISTICS) 358 { 359 pool_allocator_usage.register_instance_overhead (m_elt_size, this); 360 } 361 362 #ifdef ENABLE_VALGRIND_ANNOTATIONS 363 size = m_elt_size - offsetof (allocation_object, u.data); 364 #endif 365 366 /* If there are no more free elements, make some more!. */ 367 if (!m_returned_free_list) 368 { 369 char *block; 370 if (!m_virgin_elts_remaining) 371 { 372 allocation_pool_list *block_header; 373 374 /* Make the block. */ 375 block = reinterpret_cast<char *> (TBlockAllocator::allocate ()); 376 block_header = new (block) allocation_pool_list; 377 block += align_eight (sizeof (allocation_pool_list)); 378 379 /* Throw it on the block list. */ 380 block_header->next = m_block_list; 381 m_block_list = block_header; 382 383 /* Make the block available for allocation. */ 384 m_virgin_free_list = block; 385 m_virgin_elts_remaining = m_elts_per_block; 386 387 /* Also update the number of elements we have free/allocated, and 388 increment the allocated block count. */ 389 m_elts_allocated += m_elts_per_block; 390 m_elts_free += m_elts_per_block; 391 m_blocks_allocated += 1; 392 } 393 394 /* We now know that we can take the first elt off the virgin list and 395 put it on the returned list. */ 396 block = m_virgin_free_list; 397 header = (allocation_pool_list*) allocation_object::get_data (block); 398 header->next = NULL; 399 400 /* Mark the element to be free. */ 401 #if CHECKING_P 402 ((allocation_object*) block)->id = 0; 403 #endif 404 VALGRIND_DISCARD (VALGRIND_MAKE_MEM_NOACCESS (header,size)); 405 m_returned_free_list = header; 406 m_virgin_free_list += m_elt_size; 407 m_virgin_elts_remaining--; 408 409 } 410 411 /* Pull the first free element from the free list, and return it. */ 412 header = m_returned_free_list; 413 VALGRIND_DISCARD (VALGRIND_MAKE_MEM_DEFINED (header, sizeof (*header))); 414 m_returned_free_list = header->next; 415 m_elts_free--; 416 417 /* Set the ID for element. */ 418 #if CHECKING_P 419 allocation_object::get_instance (header)->id = m_id; 420 #endif 421 VALGRIND_DISCARD (VALGRIND_MAKE_MEM_UNDEFINED (header, size)); 422 423 return (void *)(header); 424 } 425 426 /* Puts PTR back on POOL's free list. */ 427 template <typename TBlockAllocator> 428 inline void 429 base_pool_allocator <TBlockAllocator>::remove (void *object) 430 { 431 int size = m_elt_size - offsetof (allocation_object, u.data); 432 433 if (flag_checking) 434 { 435 gcc_assert (m_initialized); 436 gcc_assert (object 437 /* Check if we free more than we allocated. */ 438 && m_elts_free < m_elts_allocated); 439 #if CHECKING_P 440 /* Check whether the PTR was allocated from POOL. */ 441 gcc_assert (m_id == allocation_object::get_instance (object)->id); 442 #endif 443 444 memset (object, 0xaf, size); 445 } 446 447 #if CHECKING_P 448 /* Mark the element to be free. */ 449 allocation_object::get_instance (object)->id = 0; 450 #endif 451 452 allocation_pool_list *header = new (object) allocation_pool_list; 453 header->next = m_returned_free_list; 454 m_returned_free_list = header; 455 VALGRIND_DISCARD (VALGRIND_MAKE_MEM_NOACCESS (object, size)); 456 m_elts_free++; 457 458 if (GATHER_STATISTICS) 459 { 460 pool_allocator_usage.release_instance_overhead (this, m_elt_size); 461 } 462 } 463 464 /* Number of elements currently active (not returned to pool). Used for cheap 465 consistency checks. */ 466 template <typename TBlockAllocator> 467 inline size_t 468 base_pool_allocator <TBlockAllocator>::num_elts_current () 469 { 470 return m_elts_allocated - m_elts_free; 471 } 472 473 /* Specialization of base_pool_allocator which should be used in most cases. 474 Another specialization may be needed, if object size is greater than 475 memory_block_pool::block_size (64 KB). */ 476 typedef base_pool_allocator <memory_block_pool> pool_allocator; 477 478 /* Type based memory pool allocator. */ 479 template <typename T> 480 class object_allocator 481 { 482 public: 483 /* Default constructor for pool allocator called NAME. */ 484 object_allocator (const char *name CXX_MEM_STAT_INFO): 485 m_allocator (name, sizeof (T) PASS_MEM_STAT) {} 486 487 inline void 488 release () 489 { 490 m_allocator.release (); 491 } 492 493 inline void release_if_empty () 494 { 495 m_allocator.release_if_empty (); 496 } 497 498 499 /* Allocate memory for instance of type T and call a default constructor. */ 500 501 inline T * 502 allocate () ATTRIBUTE_MALLOC 503 { 504 return ::new (m_allocator.allocate ()) T; 505 } 506 507 /* Allocate memory for instance of type T and return void * that 508 could be used in situations where a default constructor is not provided 509 by the class T. */ 510 511 inline void * 512 allocate_raw () ATTRIBUTE_MALLOC 513 { 514 return m_allocator.allocate (); 515 } 516 517 inline void 518 remove (T *object) 519 { 520 /* Call destructor. */ 521 object->~T (); 522 523 m_allocator.remove (object); 524 } 525 526 inline size_t 527 num_elts_current () 528 { 529 return m_allocator.num_elts_current (); 530 } 531 532 private: 533 pool_allocator m_allocator; 534 }; 535 536 /* Store information about each particular alloc_pool. Note that this 537 will underestimate the amount the amount of storage used by a small amount: 538 1) The overhead in a pool is not accounted for. 539 2) The unallocated elements in a block are not accounted for. Note 540 that this can at worst case be one element smaller that the block 541 size for that pool. */ 542 struct alloc_pool_descriptor 543 { 544 /* Number of pools allocated. */ 545 unsigned long created; 546 /* Gross allocated storage. */ 547 unsigned long allocated; 548 /* Amount of currently active storage. */ 549 unsigned long current; 550 /* Peak amount of storage used. */ 551 unsigned long peak; 552 /* Size of element in the pool. */ 553 int elt_size; 554 }; 555 556 /* Helper for classes that do not provide default ctor. */ 557 558 template <typename T> 559 inline void * 560 operator new (size_t, object_allocator<T> &a) 561 { 562 return a.allocate_raw (); 563 } 564 565 /* Hashtable mapping alloc_pool names to descriptors. */ 566 extern hash_map<const char *, alloc_pool_descriptor> *alloc_pool_hash; 567 568 569 #endif 570