Merge V8 at 3.9.24.13
Bug: 5688872
Change-Id: Id0aa8d23375030494d3189c31774059c0f5398fc
diff --git a/src/hashmap.h b/src/hashmap.h
index 5c13212..5aeb895 100644
--- a/src/hashmap.h
+++ b/src/hashmap.h
@@ -1,4 +1,4 @@
-// Copyright 2011 the V8 project authors. All rights reserved.
+// Copyright 2012 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
@@ -29,39 +29,22 @@
#define V8_HASHMAP_H_
#include "allocation.h"
+#include "checks.h"
+#include "utils.h"
namespace v8 {
namespace internal {
-
-// Allocator defines the memory allocator interface
-// used by HashMap and implements a default allocator.
-class Allocator BASE_EMBEDDED {
+template<class AllocationPolicy>
+class TemplateHashMapImpl {
public:
- virtual ~Allocator() {}
- virtual void* New(size_t size) { return Malloced::New(size); }
- virtual void Delete(void* p) { Malloced::Delete(p); }
-};
-
-
-class HashMap {
- public:
- static Allocator DefaultAllocator;
-
typedef bool (*MatchFun) (void* key1, void* key2);
- // Dummy constructor. This constructor doesn't set up the hash
- // map properly so don't use it unless you have good reason (e.g.,
- // you know that the HashMap will never be used).
- HashMap();
-
// initial_capacity is the size of the initial hash map;
// it must be a power of 2 (and thus must not be 0).
- explicit HashMap(MatchFun match,
- Allocator* allocator = &DefaultAllocator,
- uint32_t initial_capacity = 8);
+ TemplateHashMapImpl(MatchFun match, uint32_t initial_capacity = 8);
- ~HashMap();
+ ~TemplateHashMapImpl();
// HashMap entries are (key, value, hash) triplets.
// Some clients may not need to use the value slot
@@ -105,7 +88,6 @@
Entry* Next(Entry* p) const;
private:
- Allocator* allocator_;
MatchFun match_;
Entry* map_;
uint32_t capacity_;
@@ -117,6 +99,241 @@
void Resize();
};
+typedef TemplateHashMapImpl<FreeStoreAllocationPolicy> HashMap;
+
+template<class P>
+TemplateHashMapImpl<P>::TemplateHashMapImpl(MatchFun match,
+ uint32_t initial_capacity) {
+ match_ = match;
+ Initialize(initial_capacity);
+}
+
+
+template<class P>
+TemplateHashMapImpl<P>::~TemplateHashMapImpl() {
+ P::Delete(map_);
+}
+
+
+template<class P>
+typename TemplateHashMapImpl<P>::Entry* TemplateHashMapImpl<P>::Lookup(
+ void* key, uint32_t hash, bool insert) {
+ // Find a matching entry.
+ Entry* p = Probe(key, hash);
+ if (p->key != NULL) {
+ return p;
+ }
+
+ // No entry found; insert one if necessary.
+ if (insert) {
+ p->key = key;
+ p->value = NULL;
+ p->hash = hash;
+ occupancy_++;
+
+ // Grow the map if we reached >= 80% occupancy.
+ if (occupancy_ + occupancy_/4 >= capacity_) {
+ Resize();
+ p = Probe(key, hash);
+ }
+
+ return p;
+ }
+
+ // No entry found and none inserted.
+ return NULL;
+}
+
+
+template<class P>
+void TemplateHashMapImpl<P>::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;
+ }
+
+ // 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.
+ ASSERT(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_--;
+}
+
+
+template<class P>
+void TemplateHashMapImpl<P>::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 P>
+typename TemplateHashMapImpl<P>::Entry* TemplateHashMapImpl<P>::Start() const {
+ return Next(map_ - 1);
+}
+
+
+template<class P>
+typename TemplateHashMapImpl<P>::Entry* TemplateHashMapImpl<P>::Next(Entry* p)
+ const {
+ const Entry* end = map_end();
+ ASSERT(map_ - 1 <= p && p < end);
+ for (p++; p < end; p++) {
+ if (p->key != NULL) {
+ return p;
+ }
+ }
+ return NULL;
+}
+
+
+template<class P>
+typename TemplateHashMapImpl<P>::Entry* TemplateHashMapImpl<P>::Probe(void* key,
+ uint32_t hash) {
+ ASSERT(key != NULL);
+
+ ASSERT(IsPowerOf2(capacity_));
+ Entry* p = map_ + (hash & (capacity_ - 1));
+ const Entry* end = map_end();
+ ASSERT(map_ <= p && p < end);
+
+ ASSERT(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 P>
+void TemplateHashMapImpl<P>::Initialize(uint32_t capacity) {
+ ASSERT(IsPowerOf2(capacity));
+ map_ = reinterpret_cast<Entry*>(P::New(capacity * sizeof(Entry)));
+ if (map_ == NULL) {
+ v8::internal::FatalProcessOutOfMemory("HashMap::Initialize");
+ return;
+ }
+ capacity_ = capacity;
+ Clear();
+}
+
+
+template<class P>
+void TemplateHashMapImpl<P>::Resize() {
+ Entry* map = map_;
+ uint32_t n = occupancy_;
+
+ // Allocate larger map.
+ Initialize(capacity_ * 2);
+
+ // Rehash all current entries.
+ for (Entry* p = map; n > 0; p++) {
+ if (p->key != NULL) {
+ Lookup(p->key, p->hash, true)->value = p->value;
+ n--;
+ }
+ }
+
+ // Delete old map.
+ P::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)
+ : TemplateHashMapImpl<AllocationPolicy>(match) { }
+
+ Iterator begin() const { return Iterator(this, this->Start()); }
+ Iterator end() const { return Iterator(this, NULL); }
+ Iterator find(Key* key, bool insert = false) {
+ return Iterator(this, this->Lookup(key, key->Hash(), insert));
+ }
+};
} } // namespace v8::internal