// Copyright 2014 the V8 project authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "src/compiler/node-cache.h"
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#include <cstring>
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#include "src/globals.h"
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#include "src/zone/zone-containers.h"
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#include "src/zone/zone.h"
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namespace v8 {
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namespace internal {
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namespace compiler {
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namespace {
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enum { kInitialSize = 16u, kLinearProbe = 5u };
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} // namespace
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template <typename Key, typename Hash, typename Pred>
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struct NodeCache<Key, Hash, Pred>::Entry {
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Key key_;
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Node* value_;
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};
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template <typename Key, typename Hash, typename Pred>
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bool NodeCache<Key, Hash, Pred>::Resize(Zone* zone) {
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if (size_ >= max_) return false; // Don't grow past the maximum size.
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// Allocate a new block of entries 4x the size.
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Entry* old_entries = entries_;
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size_t old_size = size_ + kLinearProbe;
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size_ *= 4;
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size_t num_entries = size_ + kLinearProbe;
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entries_ = zone->NewArray<Entry>(num_entries);
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memset(entries_, 0, sizeof(Entry) * num_entries);
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// Insert the old entries into the new block.
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for (size_t i = 0; i < old_size; ++i) {
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Entry* old = &old_entries[i];
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if (old->value_) {
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size_t hash = hash_(old->key_);
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size_t start = hash & (size_ - 1);
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size_t end = start + kLinearProbe;
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for (size_t j = start; j < end; ++j) {
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Entry* entry = &entries_[j];
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if (!entry->value_) {
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entry->key_ = old->key_;
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entry->value_ = old->value_;
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break;
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}
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}
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}
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}
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return true;
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}
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template <typename Key, typename Hash, typename Pred>
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Node** NodeCache<Key, Hash, Pred>::Find(Zone* zone, Key key) {
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size_t hash = hash_(key);
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if (!entries_) {
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// Allocate the initial entries and insert the first entry.
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size_t num_entries = kInitialSize + kLinearProbe;
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entries_ = zone->NewArray<Entry>(num_entries);
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size_ = kInitialSize;
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memset(entries_, 0, sizeof(Entry) * num_entries);
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Entry* entry = &entries_[hash & (kInitialSize - 1)];
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entry->key_ = key;
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return &entry->value_;
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}
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for (;;) {
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// Search up to N entries after (linear probing).
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size_t start = hash & (size_ - 1);
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size_t end = start + kLinearProbe;
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for (size_t i = start; i < end; i++) {
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Entry* entry = &entries_[i];
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if (pred_(entry->key_, key)) return &entry->value_;
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if (!entry->value_) {
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entry->key_ = key;
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return &entry->value_;
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}
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}
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if (!Resize(zone)) break; // Don't grow past the maximum size.
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}
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// If resized to maximum and still didn't find space, overwrite an entry.
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Entry* entry = &entries_[hash & (size_ - 1)];
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entry->key_ = key;
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entry->value_ = nullptr;
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return &entry->value_;
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}
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template <typename Key, typename Hash, typename Pred>
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void NodeCache<Key, Hash, Pred>::GetCachedNodes(ZoneVector<Node*>* nodes) {
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if (entries_) {
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for (size_t i = 0; i < size_ + kLinearProbe; i++) {
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if (entries_[i].value_) nodes->push_back(entries_[i].value_);
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}
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}
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}
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// -----------------------------------------------------------------------------
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// Instantiations
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template class V8_EXPORT_PRIVATE NodeCache<int32_t>;
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template class V8_EXPORT_PRIVATE NodeCache<int64_t>;
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template class V8_EXPORT_PRIVATE NodeCache<RelocInt32Key>;
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template class V8_EXPORT_PRIVATE NodeCache<RelocInt64Key>;
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} // namespace compiler
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} // namespace internal
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} // namespace v8
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