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// Copyright 2011 the V8 project authors. All rights reserved.
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following
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// disclaimer in the documentation and/or other materials provided
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// with the distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived
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// from this software without specific prior written permission.
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#ifndef V8_SCOPEINFO_H_
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#define V8_SCOPEINFO_H_
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#include "allocation.h"
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#include "variables.h"
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// Cache for mapping (data, property name) into context slot index.
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// The cache contains both positive and negative results.
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// Slot index equals -1 means the property is absent.
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// Cleared at startup and prior to mark sweep collection.
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class ContextSlotCache {
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// Lookup context slot index for (data, name).
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// If absent, kNotFound is returned.
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int Lookup(Object* data,
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InitializationFlag* init_flag);
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// Update an element in the cache.
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void Update(Object* data,
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InitializationFlag init_flag,
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static const int kNotFound = -2;
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for (int i = 0; i < kLength; ++i) {
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values_[i] = kNotFound;
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inline static int Hash(Object* data, String* name);
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void ValidateEntry(Object* data,
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InitializationFlag init_flag,
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static const int kLength = 256;
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Value(VariableMode mode,
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InitializationFlag init_flag,
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ASSERT(ModeField::is_valid(mode));
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ASSERT(InitField::is_valid(init_flag));
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ASSERT(IndexField::is_valid(index));
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value_ = ModeField::encode(mode) |
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IndexField::encode(index) |
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InitField::encode(init_flag);
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ASSERT(mode == this->mode());
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ASSERT(init_flag == this->initialization_flag());
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ASSERT(index == this->index());
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explicit inline Value(uint32_t value) : value_(value) {}
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uint32_t raw() { return value_; }
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VariableMode mode() { return ModeField::decode(value_); }
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InitializationFlag initialization_flag() {
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return InitField::decode(value_);
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int index() { return IndexField::decode(value_); }
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// Bit fields in value_ (type, shift, size). Must be public so the
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// constants can be embedded in generated code.
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class ModeField: public BitField<VariableMode, 0, 3> {};
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class InitField: public BitField<InitializationFlag, 3, 1> {};
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class IndexField: public BitField<int, 4, 32-4> {};
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uint32_t values_[kLength];
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friend class Isolate;
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DISALLOW_COPY_AND_ASSIGN(ContextSlotCache);
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} } // namespace v8::internal
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#endif // V8_SCOPEINFO_H_