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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"
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 Mode {
// User declared variables:
VAR, // declared via 'var', and 'function' declarations
CONST, // declared via 'const' declarations
// Variables introduced by the compiler:
DYNAMIC, // always require dynamic lookup (we don't know
// the declaration)
DYNAMIC_GLOBAL, // requires dynamic lookup, but we know that the
// variable is global unless it has been shadowed
// by an eval-introduced variable
DYNAMIC_LOCAL, // requires dynamic lookup, but we know that the
// variable is local and where it is unless it
// has been shadowed by an eval-introduced
// variable
INTERNAL, // like VAR, but not user-visible (may or may not
// be in a context)
TEMPORARY // temporary variables (not user-visible), never
// in a context
};
enum Kind {
NORMAL,
THIS,
ARGUMENTS
};
Variable(Scope* scope,
Handle<String> name,
Mode mode,
bool is_valid_lhs,
Kind kind);
// Printing support
static const char* Mode2String(Mode mode);
// Type testing & conversion. Global variables are not slots.
Property* AsProperty() const;
Slot* AsSlot() const;
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_; }
Mode mode() const { return mode_; }
bool is_accessed_from_inner_scope() const {
return is_accessed_from_inner_scope_;
}
void MarkAsAccessedFromInnerScope() {
is_accessed_from_inner_scope_ = true;
}
bool is_used() { return is_used_; }
void set_is_used(bool flag) { is_used_ = flag; }
bool IsVariable(Handle<String> n) const {
return !is_this() && name().is_identical_to(n);
}
bool IsStackAllocated() const;
bool IsParameter() const; // Includes 'this'.
bool IsStackLocal() const;
bool IsContextSlot() const;
bool is_dynamic() const {
return (mode_ == DYNAMIC ||
mode_ == DYNAMIC_GLOBAL ||
mode_ == DYNAMIC_LOCAL);
}
bool is_global() const;
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()) &&
(mode_ == DYNAMIC || mode_ == DYNAMIC_GLOBAL);
}
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;
}
Slot* rewrite() const { return rewrite_; }
void set_rewrite(Slot* slot) { rewrite_ = slot; }
private:
Scope* scope_;
Handle<String> name_;
Mode mode_;
Kind kind_;
Variable* local_if_not_shadowed_;
// Code generation.
Slot* rewrite_;
// Valid as a LHS? (const and this are not valid LHS, for example)
bool is_valid_LHS_;
// Usage info.
bool is_accessed_from_inner_scope_; // set by variable resolver
bool is_used_;
};
} } // namespace v8::internal
#endif // V8_VARIABLES_H_
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