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// Copyright 2011 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:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#ifndef V8_VARIABLES_H_
#define V8_VARIABLES_H_
#include "zone.h"
#include "interface.h"
namespace v8 {
namespace internal {
// The AST refers to variables via VariableProxies - placeholders for the actual
// variables. Variables themselves are never directly referred to from the AST,
// they are maintained by scopes, and referred to from VariableProxies and Slots
// after binding and variable allocation.
class Variable: public ZoneObject {
public:
enum Kind {
NORMAL,
THIS,
ARGUMENTS
};
enum Location {
// Before and during variable allocation, a variable whose location is
// not yet determined. After allocation, a variable looked up as a
// property on the global object (and possibly absent). name() is the
// variable name, index() is invalid.
UNALLOCATED,
// A slot in the parameter section on the stack. index() is the
// parameter index, counting left-to-right. The receiver is index -1;
// the first parameter is index 0.
PARAMETER,
// A slot in the local section on the stack. index() is the variable
// index in the stack frame, starting at 0.
LOCAL,
// An indexed slot in a heap context. index() is the variable index in
// the context object on the heap, starting at 0. scope() is the
// corresponding scope.
CONTEXT,
// A named slot in a heap context. name() is the variable name in the
// context object on the heap, with lookup starting at the current
// context. index() is invalid.
LOOKUP
};
Variable(Scope* scope,
Handle<String> name,
VariableMode mode,
bool is_valid_lhs,
Kind kind,
InitializationFlag initialization_flag,
Interface* interface = Interface::NewValue());
// Printing support
static const char* Mode2String(VariableMode mode);
bool IsValidLeftHandSide() { return is_valid_LHS_; }
// The source code for an eval() call may refer to a variable that is
// in an outer scope about which we don't know anything (it may not
// be the global scope). scope() is NULL in that case. Currently the
// scope is only used to follow the context chain length.
Scope* scope() const { return scope_; }
Handle<String> name() const { return name_; }
VariableMode mode() const { return mode_; }
bool has_forced_context_allocation() const {
return force_context_allocation_;
}
void ForceContextAllocation() {
ASSERT(mode_ != TEMPORARY);
force_context_allocation_ = true;
}
bool is_used() { return is_used_; }
void set_is_used(bool flag) { is_used_ = flag; }
int initializer_position() { return initializer_position_; }
void set_initializer_position(int pos) { initializer_position_ = pos; }
bool IsVariable(Handle<String> n) const {
return !is_this() && name().is_identical_to(n);
}
bool IsUnallocated() const { return location_ == UNALLOCATED; }
bool IsParameter() const { return location_ == PARAMETER; }
bool IsStackLocal() const { return location_ == LOCAL; }
bool IsStackAllocated() const { return IsParameter() || IsStackLocal(); }
bool IsContextSlot() const { return location_ == CONTEXT; }
bool IsLookupSlot() const { return location_ == LOOKUP; }
bool IsGlobalObjectProperty() const;
bool is_dynamic() const { return IsDynamicVariableMode(mode_); }
bool is_const_mode() const { return IsImmutableVariableMode(mode_); }
bool binding_needs_init() const {
return initialization_flag_ == kNeedsInitialization;
}
bool is_this() const { return kind_ == THIS; }
bool is_arguments() const { return kind_ == ARGUMENTS; }
// True if the variable is named eval and not known to be shadowed.
bool is_possibly_eval() const {
return IsVariable(FACTORY->eval_symbol());
}
Variable* local_if_not_shadowed() const {
ASSERT(mode_ == DYNAMIC_LOCAL && local_if_not_shadowed_ != NULL);
return local_if_not_shadowed_;
}
void set_local_if_not_shadowed(Variable* local) {
local_if_not_shadowed_ = local;
}
Location location() const { return location_; }
int index() const { return index_; }
InitializationFlag initialization_flag() const {
return initialization_flag_;
}
Interface* interface() const { return interface_; }
void AllocateTo(Location location, int index) {
location_ = location;
index_ = index;
}
static int CompareIndex(Variable* const* v, Variable* const* w);
private:
Scope* scope_;
Handle<String> name_;
VariableMode mode_;
Kind kind_;
Location location_;
int index_;
int initializer_position_;
// If this field is set, this variable references the stored locally bound
// variable, but it might be shadowed by variable bindings introduced by
// non-strict 'eval' calls between the reference scope (inclusive) and the
// binding scope (exclusive).
Variable* local_if_not_shadowed_;
// Valid as a LHS? (const and this are not valid LHS, for example)
bool is_valid_LHS_;
// Usage info.
bool force_context_allocation_; // set by variable resolver
bool is_used_;
InitializationFlag initialization_flag_;
// Module type info.
Interface* interface_;
};
} } // namespace v8::internal
#endif // V8_VARIABLES_H_
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