Merge V8 5.3.332.45. DO NOT MERGE
Test: Manual
FPIIM-449
Change-Id: Id3254828b068abdea3cb10442e0172a8c9a98e03
(cherry picked from commit 13e2dadd00298019ed862f2b2fc5068bba730bcf)
diff --git a/src/base/hashmap.h b/src/base/hashmap.h
new file mode 100644
index 0000000..efb5dc8
--- /dev/null
+++ b/src/base/hashmap.h
@@ -0,0 +1,352 @@
+// Copyright 2012 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// The reason we write our own hash map instead of using unordered_map in STL,
+// is that STL containers use a mutex pool on debug build, which will lead to
+// deadlock when we are using async signal handler.
+
+#ifndef V8_BASE_HASHMAP_H_
+#define V8_BASE_HASHMAP_H_
+
+#include <stdlib.h>
+
+#include "src/base/bits.h"
+#include "src/base/logging.h"
+
+namespace v8 {
+namespace base {
+
+class DefaultAllocationPolicy {
+ public:
+ V8_INLINE void* New(size_t size) { return malloc(size); }
+ V8_INLINE static void Delete(void* p) { free(p); }
+};
+
+template <class AllocationPolicy>
+class TemplateHashMapImpl {
+ public:
+ typedef bool (*MatchFun)(void* key1, void* key2);
+
+ // The default capacity. This is used by the call sites which want
+ // to pass in a non-default AllocationPolicy but want to use the
+ // default value of capacity specified by the implementation.
+ static const uint32_t kDefaultHashMapCapacity = 8;
+
+ // initial_capacity is the size of the initial hash map;
+ // it must be a power of 2 (and thus must not be 0).
+ TemplateHashMapImpl(MatchFun match,
+ uint32_t capacity = kDefaultHashMapCapacity,
+ AllocationPolicy allocator = AllocationPolicy());
+
+ ~TemplateHashMapImpl();
+
+ // HashMap entries are (key, value, hash) triplets.
+ // Some clients may not need to use the value slot
+ // (e.g. implementers of sets, where the key is the value).
+ struct Entry {
+ void* key;
+ void* value;
+ uint32_t hash; // The full hash value for key
+ int order; // If you never remove entries this is the insertion order.
+ };
+
+ // If an entry with matching key is found, returns that entry.
+ // Otherwise, NULL is returned.
+ Entry* Lookup(void* key, uint32_t hash) const;
+
+ // If an entry with matching key is found, returns that entry.
+ // If no matching entry is found, a new entry is inserted with
+ // corresponding key, key hash, and NULL value.
+ Entry* LookupOrInsert(void* key, uint32_t hash,
+ AllocationPolicy allocator = AllocationPolicy());
+
+ // Removes the entry with matching key.
+ // It returns the value of the deleted entry
+ // or null if there is no value for such key.
+ void* Remove(void* key, uint32_t hash);
+
+ // Empties the hash map (occupancy() == 0).
+ void Clear();
+
+ // The number of (non-empty) entries in the table.
+ uint32_t occupancy() const { return occupancy_; }
+
+ // The capacity of the table. The implementation
+ // makes sure that occupancy is at most 80% of
+ // the table capacity.
+ uint32_t capacity() const { return capacity_; }
+
+ // Iteration
+ //
+ // for (Entry* p = map.Start(); p != NULL; p = map.Next(p)) {
+ // ...
+ // }
+ //
+ // If entries are inserted during iteration, the effect of
+ // calling Next() is undefined.
+ Entry* Start() const;
+ Entry* Next(Entry* p) const;
+
+ // Some match functions defined for convenience.
+ static bool PointersMatch(void* key1, void* key2) { return key1 == key2; }
+
+ private:
+ MatchFun match_;
+ Entry* map_;
+ uint32_t capacity_;
+ uint32_t occupancy_;
+
+ Entry* map_end() const { return map_ + capacity_; }
+ Entry* Probe(void* key, uint32_t hash) const;
+ void Initialize(uint32_t capacity, AllocationPolicy allocator);
+ void Resize(AllocationPolicy allocator);
+};
+
+typedef TemplateHashMapImpl<DefaultAllocationPolicy> HashMap;
+
+template <class AllocationPolicy>
+TemplateHashMapImpl<AllocationPolicy>::TemplateHashMapImpl(
+ MatchFun match, uint32_t initial_capacity, AllocationPolicy allocator) {
+ match_ = match;
+ Initialize(initial_capacity, allocator);
+}
+
+template <class AllocationPolicy>
+TemplateHashMapImpl<AllocationPolicy>::~TemplateHashMapImpl() {
+ AllocationPolicy::Delete(map_);
+}
+
+template <class AllocationPolicy>
+typename TemplateHashMapImpl<AllocationPolicy>::Entry*
+TemplateHashMapImpl<AllocationPolicy>::Lookup(void* key, uint32_t hash) const {
+ Entry* p = Probe(key, hash);
+ return p->key != NULL ? p : NULL;
+}
+
+template <class AllocationPolicy>
+typename TemplateHashMapImpl<AllocationPolicy>::Entry*
+TemplateHashMapImpl<AllocationPolicy>::LookupOrInsert(
+ void* key, uint32_t hash, AllocationPolicy allocator) {
+ // Find a matching entry.
+ Entry* p = Probe(key, hash);
+ if (p->key != NULL) {
+ return p;
+ }
+
+ // No entry found; insert one.
+ p->key = key;
+ p->value = NULL;
+ p->hash = hash;
+ p->order = occupancy_;
+ occupancy_++;
+
+ // Grow the map if we reached >= 80% occupancy.
+ if (occupancy_ + occupancy_ / 4 >= capacity_) {
+ Resize(allocator);
+ p = Probe(key, hash);
+ }
+
+ return p;
+}
+
+template <class AllocationPolicy>
+void* TemplateHashMapImpl<AllocationPolicy>::Remove(void* key, uint32_t hash) {
+ // Lookup the entry for the key to remove.
+ Entry* p = Probe(key, hash);
+ if (p->key == NULL) {
+ // Key not found nothing to remove.
+ return NULL;
+ }
+
+ void* value = p->value;
+ // To remove an entry we need to ensure that it does not create an empty
+ // entry that will cause the search for another entry to stop too soon. If all
+ // the entries between the entry to remove and the next empty slot have their
+ // initial position inside this interval, clearing the entry to remove will
+ // not break the search. If, while searching for the next empty entry, an
+ // entry is encountered which does not have its initial position between the
+ // entry to remove and the position looked at, then this entry can be moved to
+ // the place of the entry to remove without breaking the search for it. The
+ // entry made vacant by this move is now the entry to remove and the process
+ // starts over.
+ // Algorithm from http://en.wikipedia.org/wiki/Open_addressing.
+
+ // This guarantees loop termination as there is at least one empty entry so
+ // eventually the removed entry will have an empty entry after it.
+ DCHECK(occupancy_ < capacity_);
+
+ // p is the candidate entry to clear. q is used to scan forwards.
+ Entry* q = p; // Start at the entry to remove.
+ while (true) {
+ // Move q to the next entry.
+ q = q + 1;
+ if (q == map_end()) {
+ q = map_;
+ }
+
+ // All entries between p and q have their initial position between p and q
+ // and the entry p can be cleared without breaking the search for these
+ // entries.
+ if (q->key == NULL) {
+ break;
+ }
+
+ // Find the initial position for the entry at position q.
+ Entry* r = map_ + (q->hash & (capacity_ - 1));
+
+ // If the entry at position q has its initial position outside the range
+ // between p and q it can be moved forward to position p and will still be
+ // found. There is now a new candidate entry for clearing.
+ if ((q > p && (r <= p || r > q)) || (q < p && (r <= p && r > q))) {
+ *p = *q;
+ p = q;
+ }
+ }
+
+ // Clear the entry which is allowed to en emptied.
+ p->key = NULL;
+ occupancy_--;
+ return value;
+}
+
+template <class AllocationPolicy>
+void TemplateHashMapImpl<AllocationPolicy>::Clear() {
+ // Mark all entries as empty.
+ const Entry* end = map_end();
+ for (Entry* p = map_; p < end; p++) {
+ p->key = NULL;
+ }
+ occupancy_ = 0;
+}
+
+template <class AllocationPolicy>
+typename TemplateHashMapImpl<AllocationPolicy>::Entry*
+TemplateHashMapImpl<AllocationPolicy>::Start() const {
+ return Next(map_ - 1);
+}
+
+template <class AllocationPolicy>
+typename TemplateHashMapImpl<AllocationPolicy>::Entry*
+TemplateHashMapImpl<AllocationPolicy>::Next(Entry* p) const {
+ const Entry* end = map_end();
+ DCHECK(map_ - 1 <= p && p < end);
+ for (p++; p < end; p++) {
+ if (p->key != NULL) {
+ return p;
+ }
+ }
+ return NULL;
+}
+
+template <class AllocationPolicy>
+typename TemplateHashMapImpl<AllocationPolicy>::Entry*
+TemplateHashMapImpl<AllocationPolicy>::Probe(void* key, uint32_t hash) const {
+ DCHECK(key != NULL);
+
+ DCHECK(base::bits::IsPowerOfTwo32(capacity_));
+ Entry* p = map_ + (hash & (capacity_ - 1));
+ const Entry* end = map_end();
+ DCHECK(map_ <= p && p < end);
+
+ DCHECK(occupancy_ < capacity_); // Guarantees loop termination.
+ while (p->key != NULL && (hash != p->hash || !match_(key, p->key))) {
+ p++;
+ if (p >= end) {
+ p = map_;
+ }
+ }
+
+ return p;
+}
+
+template <class AllocationPolicy>
+void TemplateHashMapImpl<AllocationPolicy>::Initialize(
+ uint32_t capacity, AllocationPolicy allocator) {
+ DCHECK(base::bits::IsPowerOfTwo32(capacity));
+ map_ = reinterpret_cast<Entry*>(allocator.New(capacity * sizeof(Entry)));
+ if (map_ == NULL) {
+ FATAL("Out of memory: HashMap::Initialize");
+ return;
+ }
+ capacity_ = capacity;
+ Clear();
+}
+
+template <class AllocationPolicy>
+void TemplateHashMapImpl<AllocationPolicy>::Resize(AllocationPolicy allocator) {
+ Entry* map = map_;
+ uint32_t n = occupancy_;
+
+ // Allocate larger map.
+ Initialize(capacity_ * 2, allocator);
+
+ // Rehash all current entries.
+ for (Entry* p = map; n > 0; p++) {
+ if (p->key != NULL) {
+ Entry* entry = LookupOrInsert(p->key, p->hash, allocator);
+ entry->value = p->value;
+ entry->order = p->order;
+ n--;
+ }
+ }
+
+ // Delete old map.
+ AllocationPolicy::Delete(map);
+}
+
+// A hash map for pointer keys and values with an STL-like interface.
+template <class Key, class Value, class AllocationPolicy>
+class TemplateHashMap : private TemplateHashMapImpl<AllocationPolicy> {
+ public:
+ STATIC_ASSERT(sizeof(Key*) == sizeof(void*)); // NOLINT
+ STATIC_ASSERT(sizeof(Value*) == sizeof(void*)); // NOLINT
+ struct value_type {
+ Key* first;
+ Value* second;
+ };
+
+ class Iterator {
+ public:
+ Iterator& operator++() {
+ entry_ = map_->Next(entry_);
+ return *this;
+ }
+
+ value_type* operator->() { return reinterpret_cast<value_type*>(entry_); }
+ bool operator!=(const Iterator& other) { return entry_ != other.entry_; }
+
+ private:
+ Iterator(const TemplateHashMapImpl<AllocationPolicy>* map,
+ typename TemplateHashMapImpl<AllocationPolicy>::Entry* entry)
+ : map_(map), entry_(entry) {}
+
+ const TemplateHashMapImpl<AllocationPolicy>* map_;
+ typename TemplateHashMapImpl<AllocationPolicy>::Entry* entry_;
+
+ friend class TemplateHashMap;
+ };
+
+ TemplateHashMap(
+ typename TemplateHashMapImpl<AllocationPolicy>::MatchFun match,
+ AllocationPolicy allocator = AllocationPolicy())
+ : TemplateHashMapImpl<AllocationPolicy>(
+ match,
+ TemplateHashMapImpl<AllocationPolicy>::kDefaultHashMapCapacity,
+ allocator) {}
+
+ Iterator begin() const { return Iterator(this, this->Start()); }
+ Iterator end() const { return Iterator(this, NULL); }
+ Iterator find(Key* key, bool insert = false,
+ AllocationPolicy allocator = AllocationPolicy()) {
+ if (insert) {
+ return Iterator(this, this->LookupOrInsert(key, key->Hash(), allocator));
+ }
+ return Iterator(this, this->Lookup(key, key->Hash()));
+ }
+};
+
+} // namespace base
+} // namespace v8
+
+#endif // V8_BASE_HASHMAP_H_