c078783c36
Review URL: http://codereview.chromium.org/141038 git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2230 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
237 lines
8.7 KiB
C++
237 lines
8.7 KiB
C++
// Copyright 2006-2008 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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// met:
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//
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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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//
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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 "variables.h"
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namespace v8 {
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namespace internal {
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// Scope information represents information about a functions's
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// scopes (currently only one, because we don't do any inlining)
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// and the allocation of the scope's variables. Scope information
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// is stored in a compressed form with Code objects and is used
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// at runtime (stack dumps, deoptimization, etc.).
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//
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// Historical note: In other VMs built by this team, ScopeInfo was
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// usually called DebugInfo since the information was used (among
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// other things) for on-demand debugging (Self, Smalltalk). However,
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// DebugInfo seems misleading, since this information is primarily used
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// in debugging-unrelated contexts.
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// Forward defined as
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// template <class Allocator = FreeStoreAllocationPolicy> class ScopeInfo;
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template<class Allocator>
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class ScopeInfo BASE_EMBEDDED {
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public:
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// Create a ScopeInfo instance from a scope.
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explicit ScopeInfo(Scope* scope);
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// Create a ScopeInfo instance from a Code object.
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explicit ScopeInfo(Code* code);
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// Write the ScopeInfo data into a Code object, and returns the
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// amount of space that was needed. If no Code object is provided
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// (NULL handle), Serialize() only returns the amount of space needed.
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//
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// This operations requires that the Code object has the correct amount
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// of space for the ScopeInfo data; otherwise the operation fails (fatal
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// error). Any existing scope info in the Code object is simply overwritten.
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int Serialize(Code* code);
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// Garbage collection support for scope info embedded in Code objects.
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// This code is in ScopeInfo because only here we should have to know
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// about the encoding.
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static void IterateScopeInfo(Code* code, ObjectVisitor* v);
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// --------------------------------------------------------------------------
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// Lookup
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Handle<String> function_name() const { return function_name_; }
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Handle<String> parameter_name(int i) const { return parameters_[i]; }
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int number_of_parameters() const { return parameters_.length(); }
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Handle<String> stack_slot_name(int i) const { return stack_slots_[i]; }
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int number_of_stack_slots() const { return stack_slots_.length(); }
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Handle<String> context_slot_name(int i) const {
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return context_slots_[i - Context::MIN_CONTEXT_SLOTS];
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}
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int number_of_context_slots() const {
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int l = context_slots_.length();
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return l == 0 ? 0 : l + Context::MIN_CONTEXT_SLOTS;
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}
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Handle<String> LocalName(int i) const;
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int NumberOfLocals() const;
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// --------------------------------------------------------------------------
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// The following functions provide quick access to scope info details
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// for runtime routines w/o the need to explicitly create a ScopeInfo
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// object.
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//
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// ScopeInfo is the only class which should have to know about the
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// encoding of it's information in a Code object, which is why these
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// functions are in this class.
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// Does this scope call eval.
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static bool CallsEval(Code* code);
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// Return the number of stack slots for code.
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static int NumberOfStackSlots(Code* code);
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// Return the number of context slots for code.
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static int NumberOfContextSlots(Code* code);
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// Lookup support for scope info embedded in Code objects. Returns
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// the stack slot index for a given slot name if the slot is
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// present; otherwise returns a value < 0. The name must be a symbol
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// (canonicalized).
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static int StackSlotIndex(Code* code, String* name);
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// Lookup support for scope info embedded in Code objects. Returns the
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// context slot index for a given slot name if the slot is present; otherwise
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// returns a value < 0. The name must be a symbol (canonicalized).
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// If the slot is present and mode != NULL, sets *mode to the corresponding
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// mode for that variable.
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static int ContextSlotIndex(Code* code, String* name, Variable::Mode* mode);
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// Lookup support for scope info embedded in Code objects. Returns the
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// parameter index for a given parameter name if the parameter is present;
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// otherwise returns a value < 0. The name must be a symbol (canonicalized).
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static int ParameterIndex(Code* code, String* name);
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// Lookup support for scope info embedded in Code objects. Returns the
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// function context slot index if the function name is present (named
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// function expressions, only), otherwise returns a value < 0. The name
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// must be a symbol (canonicalized).
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static int FunctionContextSlotIndex(Code* code, String* name);
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// --------------------------------------------------------------------------
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// Debugging support
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#ifdef DEBUG
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void Print();
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#endif
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private:
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Handle<String> function_name_;
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bool calls_eval_;
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List<Handle<String>, Allocator > parameters_;
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List<Handle<String>, Allocator > stack_slots_;
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List<Handle<String>, Allocator > context_slots_;
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List<Variable::Mode, Allocator > context_modes_;
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};
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class ZoneScopeInfo: public ScopeInfo<ZoneListAllocationPolicy> {
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public:
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// Create a ZoneScopeInfo instance from a scope.
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explicit ZoneScopeInfo(Scope* scope)
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: ScopeInfo<ZoneListAllocationPolicy>(scope) {}
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// Create a ZoneScopeInfo instance from a Code object.
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explicit ZoneScopeInfo(Code* code)
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: ScopeInfo<ZoneListAllocationPolicy>(code) {}
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};
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// Cache for mapping (code, 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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public:
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// Lookup context slot index for (code, name).
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// If absent, kNotFound is returned.
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static int Lookup(Code* code,
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String* name,
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Variable::Mode* mode);
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// Update an element in the cache.
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static void Update(Code* code,
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String* name,
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Variable::Mode mode,
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int slot_index);
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// Clear the cache.
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static void Clear();
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static const int kNotFound = -2;
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private:
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inline static int Hash(Code* code, String* name);
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#ifdef DEBUG
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static void ValidateEntry(Code* code,
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String* name,
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Variable::Mode mode,
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int slot_index);
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#endif
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static const int kLength = 256;
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struct Key {
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Code* code;
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String* name;
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};
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struct Value {
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Value(Variable::Mode mode, int index) {
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ASSERT(ModeField::is_valid(mode));
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ASSERT(IndexField::is_valid(index));
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value_ = ModeField::encode(mode) | IndexField::encode(index);
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ASSERT(mode == this->mode());
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ASSERT(index == this->index());
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}
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inline Value(uint32_t value) : value_(value) {}
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uint32_t raw() { return value_; }
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Variable::Mode mode() { return ModeField::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<Variable::Mode, 0, 3> {};
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class IndexField: public BitField<int, 3, 32-3> {};
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private:
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uint32_t value_;
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};
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static Key keys_[kLength];
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static uint32_t values_[kLength];
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};
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} } // namespace v8::internal
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#endif // V8_SCOPEINFO_H_
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