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// Copyright 2014 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.
#include "src/compiler/node-cache.h"
#include <cstring>
#include "src/zone.h"
#include "src/zone-containers.h"
namespace v8 {
namespace internal {
namespace compiler {
namespace {
enum { kInitialSize = 16u, kLinearProbe = 5u };
} // namespace
template <typename Key, typename Hash, typename Pred>
struct NodeCache<Key, Hash, Pred>::Entry {
Key key_;
Node* value_;
};
template <typename Key, typename Hash, typename Pred>
bool NodeCache<Key, Hash, Pred>::Resize(Zone* zone) {
if (size_ >= max_) return false; // Don't grow past the maximum size.
// Allocate a new block of entries 4x the size.
Entry* old_entries = entries_;
size_t old_size = size_ + kLinearProbe;
size_ *= 4;
size_t num_entries = size_ + kLinearProbe;
entries_ = zone->NewArray<Entry>(num_entries);
memset(entries_, 0, sizeof(Entry) * num_entries);
// Insert the old entries into the new block.
for (size_t i = 0; i < old_size; ++i) {
Entry* old = &old_entries[i];
if (old->value_) {
size_t hash = hash_(old->key_);
size_t start = hash & (size_ - 1);
size_t end = start + kLinearProbe;
for (size_t j = start; j < end; ++j) {
Entry* entry = &entries_[j];
if (!entry->value_) {
entry->key_ = old->key_;
entry->value_ = old->value_;
break;
}
}
}
}
return true;
}
template <typename Key, typename Hash, typename Pred>
Node** NodeCache<Key, Hash, Pred>::Find(Zone* zone, Key key) {
size_t hash = hash_(key);
if (!entries_) {
// Allocate the initial entries and insert the first entry.
size_t num_entries = kInitialSize + kLinearProbe;
entries_ = zone->NewArray<Entry>(num_entries);
size_ = kInitialSize;
memset(entries_, 0, sizeof(Entry) * num_entries);
Entry* entry = &entries_[hash & (kInitialSize - 1)];
entry->key_ = key;
return &entry->value_;
}
for (;;) {
// Search up to N entries after (linear probing).
size_t start = hash & (size_ - 1);
size_t end = start + kLinearProbe;
for (size_t i = start; i < end; i++) {
Entry* entry = &entries_[i];
if (pred_(entry->key_, key)) return &entry->value_;
if (!entry->value_) {
entry->key_ = key;
return &entry->value_;
}
}
if (!Resize(zone)) break; // Don't grow past the maximum size.
}
// If resized to maximum and still didn't find space, overwrite an entry.
Entry* entry = &entries_[hash & (size_ - 1)];
entry->key_ = key;
entry->value_ = nullptr;
return &entry->value_;
}
template <typename Key, typename Hash, typename Pred>
void NodeCache<Key, Hash, Pred>::GetCachedNodes(ZoneVector<Node*>* nodes) {
if (entries_) {
for (size_t i = 0; i < size_ + kLinearProbe; i++) {
if (entries_[i].value_) nodes->push_back(entries_[i].value_);
}
}
}
// -----------------------------------------------------------------------------
// Instantiations
template class NodeCache<int32_t>;
template class NodeCache<int64_t>;
template class NodeCache<RelocInt32Key>;
template class NodeCache<RelocInt64Key>;
} // namespace compiler
} // namespace internal
} // namespace v8
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