1 //===-- sanitizer_addrhashmap.h ---------------------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // Concurrent uptr->T hashmap.
12 //===----------------------------------------------------------------------===//
14 #ifndef SANITIZER_ADDRHASHMAP_H
15 #define SANITIZER_ADDRHASHMAP_H
17 #include "sanitizer_common.h"
18 #include "sanitizer_mutex.h"
19 #include "sanitizer_atomic.h"
20 #include "sanitizer_allocator_internal.h"
22 namespace __sanitizer {
24 // Concurrent uptr->T hashmap.
25 // T must be a POD type, kSize is preferably a prime but can be any number.
28 // typedef AddrHashMap<uptr, 11> Map;
31 // Map::Handle h(&m, addr);
32 // use h.operator->() to access the data
33 // if h.created() then the element was just created, and the current thread
34 // has exclusive access to it
35 // otherwise the current thread has only read access to the data
38 // Map::Handle h(&m, addr, true);
39 // this will remove the data from the map in Handle dtor
40 // the current thread has exclusive access to the data
41 // if !h.exists() then the element never existed
43 template<typename T, uptr kSize>
47 atomic_uintptr_t addr;
54 Cell cells[1]; // variable len
57 static const uptr kBucketSize = 3;
62 Cell cells[kBucketSize];
70 Handle(AddrHashMap<T, kSize> *map, uptr addr);
71 Handle(AddrHashMap<T, kSize> *map, uptr addr, bool remove);
72 Handle(AddrHashMap<T, kSize> *map, uptr addr, bool remove, bool create);
80 friend AddrHashMap<T, kSize>;
81 AddrHashMap<T, kSize> *map_;
95 void acquire(Handle *h);
96 void release(Handle *h);
97 uptr calcHash(uptr addr);
100 template<typename T, uptr kSize>
101 AddrHashMap<T, kSize>::Handle::Handle(AddrHashMap<T, kSize> *map, uptr addr) {
109 template<typename T, uptr kSize>
110 AddrHashMap<T, kSize>::Handle::Handle(AddrHashMap<T, kSize> *map, uptr addr,
119 template<typename T, uptr kSize>
120 AddrHashMap<T, kSize>::Handle::Handle(AddrHashMap<T, kSize> *map, uptr addr,
121 bool remove, bool create) {
129 template<typename T, uptr kSize>
130 AddrHashMap<T, kSize>::Handle::~Handle() {
134 template <typename T, uptr kSize>
135 T *AddrHashMap<T, kSize>::Handle::operator->() {
139 template<typename T, uptr kSize>
140 bool AddrHashMap<T, kSize>::Handle::created() const {
144 template<typename T, uptr kSize>
145 bool AddrHashMap<T, kSize>::Handle::exists() const {
149 template<typename T, uptr kSize>
150 AddrHashMap<T, kSize>::AddrHashMap() {
151 table_ = (Bucket*)MmapOrDie(kSize * sizeof(table_[0]), "AddrHashMap");
154 template<typename T, uptr kSize>
155 void AddrHashMap<T, kSize>::acquire(Handle *h) {
156 uptr addr = h->addr_;
157 uptr hash = calcHash(addr);
158 Bucket *b = &table_[hash];
165 // If we want to remove the element, we need exclusive access to the bucket,
166 // so skip the lock-free phase.
171 // First try to find an existing element w/o read mutex.
173 // Check the embed cells.
174 for (uptr i = 0; i < kBucketSize; i++) {
175 Cell *c = &b->cells[i];
176 uptr addr1 = atomic_load(&c->addr, memory_order_acquire);
183 // Check the add cells with read lock.
184 if (atomic_load(&b->add, memory_order_relaxed)) {
186 AddBucket *add = (AddBucket*)atomic_load(&b->add, memory_order_relaxed);
187 for (uptr i = 0; i < add->size; i++) {
188 Cell *c = &add->cells[i];
189 uptr addr1 = atomic_load(&c->addr, memory_order_relaxed);
200 // Re-check existence under write lock.
203 for (uptr i = 0; i < kBucketSize; i++) {
204 Cell *c = &b->cells[i];
205 uptr addr1 = atomic_load(&c->addr, memory_order_relaxed);
217 AddBucket *add = (AddBucket*)atomic_load(&b->add, memory_order_relaxed);
219 for (uptr i = 0; i < add->size; i++) {
220 Cell *c = &add->cells[i];
221 uptr addr1 = atomic_load(&c->addr, memory_order_relaxed);
234 // The element does not exist, no need to create it if we want to remove.
235 if (h->remove_ || !h->create_) {
240 // Now try to create it under the mutex.
242 // See if we have a free embed cell.
243 for (uptr i = 0; i < kBucketSize; i++) {
244 Cell *c = &b->cells[i];
245 uptr addr1 = atomic_load(&c->addr, memory_order_relaxed);
252 // Store in the add cells.
254 // Allocate a new add array.
255 const uptr kInitSize = 64;
256 add = (AddBucket*)InternalAlloc(kInitSize);
257 internal_memset(add, 0, kInitSize);
258 add->cap = (kInitSize - sizeof(*add)) / sizeof(add->cells[0]) + 1;
260 atomic_store(&b->add, (uptr)add, memory_order_relaxed);
262 if (add->size == add->cap) {
263 // Grow existing add array.
264 uptr oldsize = sizeof(*add) + (add->cap - 1) * sizeof(add->cells[0]);
265 uptr newsize = oldsize * 2;
266 AddBucket *add1 = (AddBucket*)InternalAlloc(newsize);
267 internal_memset(add1, 0, newsize);
268 add1->cap = (newsize - sizeof(*add)) / sizeof(add->cells[0]) + 1;
269 add1->size = add->size;
270 internal_memcpy(add1->cells, add->cells, add->size * sizeof(add->cells[0]));
272 atomic_store(&b->add, (uptr)add1, memory_order_relaxed);
276 uptr i = add->size++;
277 Cell *c = &add->cells[i];
278 CHECK_EQ(atomic_load(&c->addr, memory_order_relaxed), 0);
283 template<typename T, uptr kSize>
284 void AddrHashMap<T, kSize>::release(Handle *h) {
287 Bucket *b = h->bucket_;
289 uptr addr1 = atomic_load(&c->addr, memory_order_relaxed);
291 // Denote completion of insertion.
293 // After the following store, the element becomes available
294 // for lock-free reads.
295 atomic_store(&c->addr, h->addr_, memory_order_release);
297 } else if (h->remove_) {
298 // Denote that the cell is empty now.
299 CHECK_EQ(addr1, h->addr_);
300 atomic_store(&c->addr, 0, memory_order_release);
301 // See if we need to compact the bucket.
302 AddBucket *add = (AddBucket*)atomic_load(&b->add, memory_order_relaxed);
303 if (h->addidx_ == -1U) {
304 // Removed from embed array, move an add element into the freed cell.
305 if (add && add->size != 0) {
306 uptr last = --add->size;
307 Cell *c1 = &add->cells[last];
309 uptr addr1 = atomic_load(&c1->addr, memory_order_relaxed);
310 atomic_store(&c->addr, addr1, memory_order_release);
311 atomic_store(&c1->addr, 0, memory_order_release);
314 // Removed from add array, compact it.
315 uptr last = --add->size;
316 Cell *c1 = &add->cells[last];
319 atomic_store(&c1->addr, 0, memory_order_relaxed);
322 if (add && add->size == 0) {
323 // FIXME(dvyukov): free add?
327 CHECK_EQ(addr1, h->addr_);
328 if (h->addidx_ != -1U)
333 template<typename T, uptr kSize>
334 uptr AddrHashMap<T, kSize>::calcHash(uptr addr) {
340 } // namespace __sanitizer
342 #endif // SANITIZER_ADDRHASHMAP_H