// Copyright 2010 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_AST_H_
#define V8_AST_H_
#include "execution.h"
#include "factory.h"
#include "jsregexp.h"
#include "jump-target.h"
#include "runtime.h"
#include "token.h"
#include "variables.h"
namespace v8 {
namespace internal {
// The abstract syntax tree is an intermediate, light-weight
// representation of the parsed JavaScript code suitable for
// compilation to native code.
// Nodes are allocated in a separate zone, which allows faster
// allocation and constant-time deallocation of the entire syntax
// tree.
// ----------------------------------------------------------------------------
// Nodes of the abstract syntax tree. Only concrete classes are
// enumerated here.
#define STATEMENT_NODE_LIST(V) \
V(Block) \
V(ExpressionStatement) \
V(EmptyStatement) \
V(IfStatement) \
V(ContinueStatement) \
V(BreakStatement) \
V(ReturnStatement) \
V(WithEnterStatement) \
V(WithExitStatement) \
V(SwitchStatement) \
V(DoWhileStatement) \
V(WhileStatement) \
V(ForStatement) \
V(ForInStatement) \
V(TryCatchStatement) \
V(TryFinallyStatement) \
V(DebuggerStatement)
#define EXPRESSION_NODE_LIST(V) \
V(FunctionLiteral) \
V(FunctionBoilerplateLiteral) \
V(Conditional) \
V(Slot) \
V(VariableProxy) \
V(Literal) \
V(RegExpLiteral) \
V(ObjectLiteral) \
V(ArrayLiteral) \
V(CatchExtensionObject) \
V(Assignment) \
V(Throw) \
V(Property) \
V(Call) \
V(CallNew) \
V(CallRuntime) \
V(UnaryOperation) \
V(CountOperation) \
V(BinaryOperation) \
V(CompareOperation) \
V(ThisFunction)
#define AST_NODE_LIST(V) \
V(Declaration) \
STATEMENT_NODE_LIST(V) \
EXPRESSION_NODE_LIST(V)
// Forward declarations
class TargetCollector;
class MaterializedLiteral;
class DefinitionInfo;
#define DEF_FORWARD_DECLARATION(type) class type;
AST_NODE_LIST(DEF_FORWARD_DECLARATION)
#undef DEF_FORWARD_DECLARATION
// Typedef only introduced to avoid unreadable code.
// Please do appreciate the required space in "> >".
typedef ZoneList<Handle<String> > ZoneStringList;
typedef ZoneList<Handle<Object> > ZoneObjectList;
class AstNode: public ZoneObject {
public:
virtual ~AstNode() { }
virtual void Accept(AstVisitor* v) = 0;
// Type testing & conversion.
virtual Statement* AsStatement() { return NULL; }
virtual ExpressionStatement* AsExpressionStatement() { return NULL; }
virtual EmptyStatement* AsEmptyStatement() { return NULL; }
virtual Expression* AsExpression() { return NULL; }
virtual Literal* AsLiteral() { return NULL; }
virtual Slot* AsSlot() { return NULL; }
virtual VariableProxy* AsVariableProxy() { return NULL; }
virtual Property* AsProperty() { return NULL; }
virtual Call* AsCall() { return NULL; }
virtual TargetCollector* AsTargetCollector() { return NULL; }
virtual BreakableStatement* AsBreakableStatement() { return NULL; }
virtual IterationStatement* AsIterationStatement() { return NULL; }
virtual UnaryOperation* AsUnaryOperation() { return NULL; }
virtual BinaryOperation* AsBinaryOperation() { return NULL; }
virtual Assignment* AsAssignment() { return NULL; }
virtual FunctionLiteral* AsFunctionLiteral() { return NULL; }
virtual MaterializedLiteral* AsMaterializedLiteral() { return NULL; }
virtual ObjectLiteral* AsObjectLiteral() { return NULL; }
virtual ArrayLiteral* AsArrayLiteral() { return NULL; }
virtual CompareOperation* AsCompareOperation() { return NULL; }
};
class Statement: public AstNode {
public:
Statement() : statement_pos_(RelocInfo::kNoPosition) {}
virtual Statement* AsStatement() { return this; }
virtual ReturnStatement* AsReturnStatement() { return NULL; }
bool IsEmpty() { return AsEmptyStatement() != NULL; }
void set_statement_pos(int statement_pos) { statement_pos_ = statement_pos; }
int statement_pos() const { return statement_pos_; }
private:
int statement_pos_;
};
class Expression: public AstNode {
public:
enum Context {
// Not assigned a context yet, or else will not be visited during
// code generation.
kUninitialized,
// Evaluated for its side effects.
kEffect,
// Evaluated for its value (and side effects).
kValue,
// Evaluated for control flow (and side effects).
kTest,
// Evaluated for control flow and side effects. Value is also
// needed if true.
kValueTest,
// Evaluated for control flow and side effects. Value is also
// needed if false.
kTestValue
};
static const int kNoLabel = -1;
Expression() : num_(kNoLabel), def_(NULL), defined_vars_(NULL) {}
virtual Expression* AsExpression() { return this; }
virtual bool IsValidLeftHandSide() { return false; }
// Symbols that cannot be parsed as array indices are considered property
// names. We do not treat symbols that can be array indexes as property
// names because [] for string objects is handled only by keyed ICs.
virtual bool IsPropertyName() { return false; }
// True if the expression does not have (evaluated) subexpressions.
// Function literals are leaves because their subexpressions are not
// evaluated.
virtual bool IsLeaf() { return false; }
// True if the expression has no side effects and is safe to
// evaluate out of order.
virtual bool IsTrivial() { return false; }
// Mark the expression as being compiled as an expression
// statement. This is used to transform postfix increments to
// (faster) prefix increments.
virtual void MarkAsStatement() { /* do nothing */ }
// Static type information for this expression.
StaticType* type() { return &type_; }
int num() { return num_; }
// AST node numbering ordered by evaluation order.
void set_num(int n) { num_ = n; }
// Data flow information.
DefinitionInfo* var_def() { return def_; }
void set_var_def(DefinitionInfo* def) { def_ = def; }
ZoneList<DefinitionInfo*>* defined_vars() { return defined_vars_; }
void set_defined_vars(ZoneList<DefinitionInfo*>* defined_vars) {
defined_vars_ = defined_vars;
}
private:
StaticType type_;
int num_;
DefinitionInfo* def_;
ZoneList<DefinitionInfo*>* defined_vars_;
};
/**
* A sentinel used during pre parsing that represents some expression
* that is a valid left hand side without having to actually build
* the expression.
*/
class ValidLeftHandSideSentinel: public Expression {
public:
virtual bool IsValidLeftHandSide() { return true; }
virtual void Accept(AstVisitor* v) { UNREACHABLE(); }
static ValidLeftHandSideSentinel* instance() { return &instance_; }
private:
static ValidLeftHandSideSentinel instance_;
};
class BreakableStatement: public Statement {
public:
enum Type {
TARGET_FOR_ANONYMOUS,
TARGET_FOR_NAMED_ONLY
};
// The labels associated with this statement. May be NULL;
// if it is != NULL, guaranteed to contain at least one entry.
ZoneStringList* labels() const { return labels_; }
// Type testing & conversion.
virtual BreakableStatement* AsBreakableStatement() { return this; }
// Code generation
BreakTarget* break_target() { return &break_target_; }
// Testers.
bool is_target_for_anonymous() const { return type_ == TARGET_FOR_ANONYMOUS; }
protected:
BreakableStatement(ZoneStringList* labels, Type type)
: labels_(labels), type_(type) {
ASSERT(labels == NULL || labels->length() > 0);
}
private:
ZoneStringList* labels_;
Type type_;
BreakTarget break_target_;
};
class Block: public BreakableStatement {
public:
Block(ZoneStringList* labels, int capacity, bool is_initializer_block)
: BreakableStatement(labels, TARGET_FOR_NAMED_ONLY),
statements_(capacity),
is_initializer_block_(is_initializer_block) { }
virtual void Accept(AstVisitor* v);
void AddStatement(Statement* statement) { statements_.Add(statement); }
ZoneList<Statement*>* statements() { return &statements_; }
bool is_initializer_block() const { return is_initializer_block_; }
private:
ZoneList<Statement*> statements_;
bool is_initializer_block_;
};
class Declaration: public AstNode {
public:
Declaration(VariableProxy* proxy, Variable::Mode mode, FunctionLiteral* fun)
: proxy_(proxy),
mode_(mode),
fun_(fun) {
ASSERT(mode == Variable::VAR || mode == Variable::CONST);
// At the moment there are no "const functions"'s in JavaScript...
ASSERT(fun == NULL || mode == Variable::VAR);
}
virtual void Accept(AstVisitor* v);
VariableProxy* proxy() const { return proxy_; }
Variable::Mode mode() const { return mode_; }
FunctionLiteral* fun() const { return fun_; } // may be NULL
private:
VariableProxy* proxy_;
Variable::Mode mode_;
FunctionLiteral* fun_;
};
class IterationStatement: public BreakableStatement {
public:
// Type testing & conversion.
virtual IterationStatement* AsIterationStatement() { return this; }
Statement* body() const { return body_; }
// Code generation
BreakTarget* continue_target() { return &continue_target_; }
protected:
explicit IterationStatement(ZoneStringList* labels)
: BreakableStatement(labels, TARGET_FOR_ANONYMOUS), body_(NULL) { }
void Initialize(Statement* body) {
body_ = body;
}
private:
Statement* body_;
BreakTarget continue_target_;
};
class DoWhileStatement: public IterationStatement {
public:
explicit DoWhileStatement(ZoneStringList* labels)
: IterationStatement(labels), cond_(NULL), condition_position_(-1) {
}
void Initialize(Expression* cond, Statement* body) {
IterationStatement::Initialize(body);
cond_ = cond;
}
virtual void Accept(AstVisitor* v);
Expression* cond() const { return cond_; }
// Position where condition expression starts. We need it to make
// the loop's condition a breakable location.
int condition_position() { return condition_position_; }
void set_condition_position(int pos) { condition_position_ = pos; }
private:
Expression* cond_;
int condition_position_;
};
class WhileStatement: public IterationStatement {
public:
explicit WhileStatement(ZoneStringList* labels)
: IterationStatement(labels),
cond_(NULL),
may_have_function_literal_(true) {
}
void Initialize(Expression* cond, Statement* body) {
IterationStatement::Initialize(body);
cond_ = cond;
}
virtual void Accept(AstVisitor* v);
Expression* cond() const { return cond_; }
bool may_have_function_literal() const {
return may_have_function_literal_;
}
private:
Expression* cond_;
// True if there is a function literal subexpression in the condition.
bool may_have_function_literal_;
friend class AstOptimizer;
};
class ForStatement: public IterationStatement {
public:
explicit ForStatement(ZoneStringList* labels)
: IterationStatement(labels),
init_(NULL),
cond_(NULL),
next_(NULL),
may_have_function_literal_(true) {
}
void Initialize(Statement* init,
Expression* cond,
Statement* next,
Statement* body) {
IterationStatement::Initialize(body);
init_ = init;
cond_ = cond;
next_ = next;
}
virtual void Accept(AstVisitor* v);
Statement* init() const { return init_; }
Expression* cond() const { return cond_; }
Statement* next() const { return next_; }
bool may_have_function_literal() const {
return may_have_function_literal_;
}
private:
Statement* init_;
Expression* cond_;
Statement* next_;
// True if there is a function literal subexpression in the condition.
bool may_have_function_literal_;
friend class AstOptimizer;
};
class ForInStatement: public IterationStatement {
public:
explicit ForInStatement(ZoneStringList* labels)
: IterationStatement(labels), each_(NULL), enumerable_(NULL) { }
void Initialize(Expression* each, Expression* enumerable, Statement* body) {
IterationStatement::Initialize(body);
each_ = each;
enumerable_ = enumerable;
}
virtual void Accept(AstVisitor* v);
Expression* each() const { return each_; }
Expression* enumerable() const { return enumerable_; }
private:
Expression* each_;
Expression* enumerable_;
};
class ExpressionStatement: public Statement {
public:
explicit ExpressionStatement(Expression* expression)
: expression_(expression) { }
virtual void Accept(AstVisitor* v);
// Type testing & conversion.
virtual ExpressionStatement* AsExpressionStatement() { return this; }
void set_expression(Expression* e) { expression_ = e; }
Expression* expression() { return expression_; }
private:
Expression* expression_;
};
class ContinueStatement: public Statement {
public:
explicit ContinueStatement(IterationStatement* target)
: target_(target) { }
virtual void Accept(AstVisitor* v);
IterationStatement* target() const { return target_; }
private:
IterationStatement* target_;
};
class BreakStatement: public Statement {
public:
explicit BreakStatement(BreakableStatement* target)
: target_(target) { }
virtual void Accept(AstVisitor* v);
BreakableStatement* target() const { return target_; }
private:
BreakableStatement* target_;
};
class ReturnStatement: public Statement {
public:
explicit ReturnStatement(Expression* expression)
: expression_(expression) { }
virtual void Accept(AstVisitor* v);
// Type testing & conversion.
virtual ReturnStatement* AsReturnStatement() { return this; }
Expression* expression() { return expression_; }
private:
Expression* expression_;
};
class WithEnterStatement: public Statement {
public:
explicit WithEnterStatement(Expression* expression, bool is_catch_block)
: expression_(expression), is_catch_block_(is_catch_block) { }
virtual void Accept(AstVisitor* v);
Expression* expression() const { return expression_; }
bool is_catch_block() const { return is_catch_block_; }
private:
Expression* expression_;
bool is_catch_block_;
};
class WithExitStatement: public Statement {
public:
WithExitStatement() { }
virtual void Accept(AstVisitor* v);
};
class CaseClause: public ZoneObject {
public:
CaseClause(Expression* label, ZoneList<Statement*>* statements)
: label_(label), statements_(statements) { }
bool is_default() const { return label_ == NULL; }
Expression* label() const {
CHECK(!is_default());
return label_;
}
JumpTarget* body_target() { return &body_target_; }
ZoneList<Statement*>* statements() const { return statements_; }
private:
Expression* label_;
JumpTarget body_target_;
ZoneList<Statement*>* statements_;
};
class SwitchStatement: public BreakableStatement {
public:
explicit SwitchStatement(ZoneStringList* labels)
: BreakableStatement(labels, TARGET_FOR_ANONYMOUS),
tag_(NULL), cases_(NULL) { }
void Initialize(Expression* tag, ZoneList<CaseClause*>* cases) {
tag_ = tag;
cases_ = cases;
}
virtual void Accept(AstVisitor* v);
Expression* tag() const { return tag_; }
ZoneList<CaseClause*>* cases() const { return cases_; }
private:
Expression* tag_;
ZoneList<CaseClause*>* cases_;
};
// If-statements always have non-null references to their then- and
// else-parts. When parsing if-statements with no explicit else-part,
// the parser implicitly creates an empty statement. Use the
// HasThenStatement() and HasElseStatement() functions to check if a
// given if-statement has a then- or an else-part containing code.
class IfStatement: public Statement {
public:
IfStatement(Expression* condition,
Statement* then_statement,
Statement* else_statement)
: condition_(condition),
then_statement_(then_statement),
else_statement_(else_statement) { }
virtual void Accept(AstVisitor* v);
bool HasThenStatement() const { return !then_statement()->IsEmpty(); }
bool HasElseStatement() const { return !else_statement()->IsEmpty(); }
Expression* condition() const { return condition_; }
Statement* then_statement() const { return then_statement_; }
Statement* else_statement() const { return else_statement_; }
private:
Expression* condition_;
Statement* then_statement_;
Statement* else_statement_;
};
// NOTE: TargetCollectors are represented as nodes to fit in the target
// stack in the compiler; this should probably be reworked.
class TargetCollector: public AstNode {
public:
explicit TargetCollector(ZoneList<BreakTarget*>* targets)
: targets_(targets) {
}
// Adds a jump target to the collector. The collector stores a pointer not
// a copy of the target to make binding work, so make sure not to pass in
// references to something on the stack.
void AddTarget(BreakTarget* target);
// Virtual behaviour. TargetCollectors are never part of the AST.
virtual void Accept(AstVisitor* v) { UNREACHABLE(); }
virtual TargetCollector* AsTargetCollector() { return this; }
ZoneList<BreakTarget*>* targets() { return targets_; }
private:
ZoneList<BreakTarget*>* targets_;
};
class TryStatement: public Statement {
public:
explicit TryStatement(Block* try_block)
: try_block_(try_block), escaping_targets_(NULL) { }
void set_escaping_targets(ZoneList<BreakTarget*>* targets) {
escaping_targets_ = targets;
}
Block* try_block() const { return try_block_; }
ZoneList<BreakTarget*>* escaping_targets() const { return escaping_targets_; }
private:
Block* try_block_;
ZoneList<BreakTarget*>* escaping_targets_;
};
class TryCatchStatement: public TryStatement {
public:
TryCatchStatement(Block* try_block,
VariableProxy* catch_var,
Block* catch_block)
: TryStatement(try_block),
catch_var_(catch_var),
catch_block_(catch_block) {
}
virtual void Accept(AstVisitor* v);
VariableProxy* catch_var() const { return catch_var_; }
Block* catch_block() const { return catch_block_; }
private:
VariableProxy* catch_var_;
Block* catch_block_;
};
class TryFinallyStatement: public TryStatement {
public:
TryFinallyStatement(Block* try_block, Block* finally_block)
: TryStatement(try_block),
finally_block_(finally_block) { }
virtual void Accept(AstVisitor* v);
Block* finally_block() const { return finally_block_; }
private:
Block* finally_block_;
};
class DebuggerStatement: public Statement {
public:
virtual void Accept(AstVisitor* v);
};
class EmptyStatement: public Statement {
public:
virtual void Accept(AstVisitor* v);
// Type testing & conversion.
virtual EmptyStatement* AsEmptyStatement() { return this; }
};
class Literal: public Expression {
public:
explicit Literal(Handle<Object> handle) : handle_(handle) { }
virtual void Accept(AstVisitor* v);
// Type testing & conversion.
virtual Literal* AsLiteral() { return this; }
// Check if this literal is identical to the other literal.
bool IsIdenticalTo(const Literal* other) const {
return handle_.is_identical_to(other->handle_);
}
virtual bool IsPropertyName() {
if (handle_->IsSymbol()) {
uint32_t ignored;
return !String::cast(*handle_)->AsArrayIndex(&ignored);
}
return false;
}
virtual bool IsLeaf() { return true; }
virtual bool IsTrivial() { return true; }
// Identity testers.
bool IsNull() const { return handle_.is_identical_to(Factory::null_value()); }
bool IsTrue() const { return handle_.is_identical_to(Factory::true_value()); }
bool IsFalse() const {
return handle_.is_identical_to(Factory::false_value());
}
Handle<Object> handle() const { return handle_; }
private:
Handle<Object> handle_;
};
// Base class for literals that needs space in the corresponding JSFunction.
class MaterializedLiteral: public Expression {
public:
explicit MaterializedLiteral(int literal_index, bool is_simple, int depth)
: literal_index_(literal_index), is_simple_(is_simple), depth_(depth) {}
virtual MaterializedLiteral* AsMaterializedLiteral() { return this; }
int literal_index() { return literal_index_; }
// A materialized literal is simple if the values consist of only
// constants and simple object and array literals.
bool is_simple() const { return is_simple_; }
int depth() const { return depth_; }
private:
int literal_index_;
bool is_simple_;
int depth_;
};
// An object literal has a boilerplate object that is used
// for minimizing the work when constructing it at runtime.
class ObjectLiteral: public MaterializedLiteral {
public:
// Property is used for passing information
// about an object literal's properties from the parser
// to the code generator.
class Property: public ZoneObject {
public:
enum Kind {
CONSTANT, // Property with constant value (compile time).
COMPUTED, // Property with computed value (execution time).
MATERIALIZED_LITERAL, // Property value is a materialized literal.
GETTER, SETTER, // Property is an accessor function.
PROTOTYPE // Property is __proto__.
};
Property(Literal* key, Expression* value);
Property(bool is_getter, FunctionLiteral* value);
Literal* key() { return key_; }
Expression* value() { return value_; }
Kind kind() { return kind_; }
bool IsCompileTimeValue();
private:
Literal* key_;
Expression* value_;
Kind kind_;
};
ObjectLiteral(Handle<FixedArray> constant_properties,
ZoneList<Property*>* properties,
int literal_index,
bool is_simple,
int depth)
: MaterializedLiteral(literal_index, is_simple, depth),
constant_properties_(constant_properties),
properties_(properties) {}
virtual ObjectLiteral* AsObjectLiteral() { return this; }
virtual void Accept(AstVisitor* v);
virtual bool IsLeaf() { return properties()->is_empty(); }
Handle<FixedArray> constant_properties() const {
return constant_properties_;
}
ZoneList<Property*>* properties() const { return properties_; }
private:
Handle<FixedArray> constant_properties_;
ZoneList<Property*>* properties_;
};
// Node for capturing a regexp literal.
class RegExpLiteral: public MaterializedLiteral {
public:
RegExpLiteral(Handle<String> pattern,
Handle<String> flags,
int literal_index)
: MaterializedLiteral(literal_index, false, 1),
pattern_(pattern),
flags_(flags) {}
virtual void Accept(AstVisitor* v);
virtual bool IsLeaf() { return true; }
Handle<String> pattern() const { return pattern_; }
Handle<String> flags() const { return flags_; }
private:
Handle<String> pattern_;
Handle<String> flags_;
};
// An array literal has a literals object that is used
// for minimizing the work when constructing it at runtime.
class ArrayLiteral: public MaterializedLiteral {
public:
ArrayLiteral(Handle<FixedArray> constant_elements,
ZoneList<Expression*>* values,
int literal_index,
bool is_simple,
int depth)
: MaterializedLiteral(literal_index, is_simple, depth),
constant_elements_(constant_elements),
values_(values) {}
virtual void Accept(AstVisitor* v);
virtual ArrayLiteral* AsArrayLiteral() { return this; }
virtual bool IsLeaf() { return values()->is_empty(); }
Handle<FixedArray> constant_elements() const { return constant_elements_; }
ZoneList<Expression*>* values() const { return values_; }
private:
Handle<FixedArray> constant_elements_;
ZoneList<Expression*>* values_;
};
// Node for constructing a context extension object for a catch block.
// The catch context extension object has one property, the catch
// variable, which should be DontDelete.
class CatchExtensionObject: public Expression {
public:
CatchExtensionObject(Literal* key, VariableProxy* value)
: key_(key), value_(value) {
}
virtual void Accept(AstVisitor* v);
Literal* key() const { return key_; }
VariableProxy* value() const { return value_; }
private:
Literal* key_;
VariableProxy* value_;
};
class VariableProxy: public Expression {
public:
virtual void Accept(AstVisitor* v);
// Type testing & conversion
virtual Property* AsProperty() {
return var_ == NULL ? NULL : var_->AsProperty();
}
virtual VariableProxy* AsVariableProxy() { return this; }
Variable* AsVariable() {
return this == NULL || var_ == NULL ? NULL : var_->AsVariable();
}
virtual bool IsValidLeftHandSide() {
return var_ == NULL ? true : var_->IsValidLeftHandSide();
}
virtual bool IsLeaf() {
ASSERT(var_ != NULL); // Variable must be resolved.
return var()->is_global() || var()->rewrite()->IsLeaf();
}
// Reading from a mutable variable is a side effect, but 'this' is
// immutable.
virtual bool IsTrivial() { return is_this(); }
bool IsVariable(Handle<String> n) {
return !is_this() && name().is_identical_to(n);
}
bool IsArguments() {
Variable* variable = AsVariable();
return (variable == NULL) ? false : variable->is_arguments();
}
Handle<String> name() const { return name_; }
Variable* var() const { return var_; }
UseCount* var_uses() { return &var_uses_; }
UseCount* obj_uses() { return &obj_uses_; }
bool is_this() const { return is_this_; }
bool inside_with() const { return inside_with_; }
// Bind this proxy to the variable var.
void BindTo(Variable* var);
protected:
Handle<String> name_;
Variable* var_; // resolved variable, or NULL
bool is_this_;
bool inside_with_;
// VariableProxy usage info.
UseCount var_uses_; // uses of the variable value
UseCount obj_uses_; // uses of the object the variable points to
VariableProxy(Handle<String> name, bool is_this, bool inside_with);
explicit VariableProxy(bool is_this);
friend class Scope;
};
class VariableProxySentinel: public VariableProxy {
public:
virtual bool IsValidLeftHandSide() { return !is_this(); }
static VariableProxySentinel* this_proxy() { return &this_proxy_; }
static VariableProxySentinel* identifier_proxy() {
return &identifier_proxy_;
}
private:
explicit VariableProxySentinel(bool is_this) : VariableProxy(is_this) { }
static VariableProxySentinel this_proxy_;
static VariableProxySentinel identifier_proxy_;
};
class Slot: public Expression {
public:
enum Type {
// A slot in the parameter section on the stack. index() is
// the parameter index, counting left-to-right, starting at 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. var()->scope() is the corresponding
// scope.
CONTEXT,
// A named slot in a heap context. var()->name() is the
// variable name in the context object on the heap,
// with lookup starting at the current context. index()
// is invalid.
LOOKUP
};
Slot(Variable* var, Type type, int index)
: var_(var), type_(type), index_(index) {
ASSERT(var != NULL);
}
virtual void Accept(AstVisitor* v);
// Type testing & conversion
virtual Slot* AsSlot() { return this; }
virtual bool IsLeaf() { return true; }
// Accessors
Variable* var() const { return var_; }
Type type() const { return type_; }
int index() const { return index_; }
bool is_arguments() const { return var_->is_arguments(); }
private:
Variable* var_;
Type type_;
int index_;
};
class Property: public Expression {
public:
// Synthetic properties are property lookups introduced by the system,
// to objects that aren't visible to the user. Function calls to synthetic
// properties should use the global object as receiver, not the base object
// of the resolved Reference.
enum Type { NORMAL, SYNTHETIC };
Property(Expression* obj, Expression* key, int pos, Type type = NORMAL)
: obj_(obj), key_(key), pos_(pos), type_(type) { }
virtual void Accept(AstVisitor* v);
// Type testing & conversion
virtual Property* AsProperty() { return this; }
virtual bool IsValidLeftHandSide() { return true; }
Expression* obj() const { return obj_; }
Expression* key() const { return key_; }
int position() const { return pos_; }
bool is_synthetic() const { return type_ == SYNTHETIC; }
// Returns a property singleton property access on 'this'. Used
// during preparsing.
static Property* this_property() { return &this_property_; }
private:
Expression* obj_;
Expression* key_;
int pos_;
Type type_;
// Dummy property used during preparsing.
static Property this_property_;
};
class Call: public Expression {
public:
Call(Expression* expression, ZoneList<Expression*>* arguments, int pos)
: expression_(expression), arguments_(arguments), pos_(pos) { }
virtual void Accept(AstVisitor* v);
// Type testing and conversion.
virtual Call* AsCall() { return this; }
Expression* expression() const { return expression_; }
ZoneList<Expression*>* arguments() const { return arguments_; }
int position() { return pos_; }
static Call* sentinel() { return &sentinel_; }
private:
Expression* expression_;
ZoneList<Expression*>* arguments_;
int pos_;
static Call sentinel_;
};
class CallNew: public Expression {
public:
CallNew(Expression* expression, ZoneList<Expression*>* arguments, int pos)
: expression_(expression), arguments_(arguments), pos_(pos) { }
virtual void Accept(AstVisitor* v);
Expression* expression() const { return expression_; }
ZoneList<Expression*>* arguments() const { return arguments_; }
int position() { return pos_; }
private:
Expression* expression_;
ZoneList<Expression*>* arguments_;
int pos_;
};
// The CallRuntime class does not represent any official JavaScript
// language construct. Instead it is used to call a C or JS function
// with a set of arguments. This is used from the builtins that are
// implemented in JavaScript (see "v8natives.js").
class CallRuntime: public Expression {
public:
CallRuntime(Handle<String> name,
Runtime::Function* function,
ZoneList<Expression*>* arguments)
: name_(name), function_(function), arguments_(arguments) { }
virtual void Accept(AstVisitor* v);
Handle<String> name() const { return name_; }
Runtime::Function* function() const { return function_; }
ZoneList<Expression*>* arguments() const { return arguments_; }
bool is_jsruntime() const { return function_ == NULL; }
private:
Handle<String> name_;
Runtime::Function* function_;
ZoneList<Expression*>* arguments_;
};
class UnaryOperation: public Expression {
public:
UnaryOperation(Token::Value op, Expression* expression)
: op_(op), expression_(expression) {
ASSERT(Token::IsUnaryOp(op));
}
virtual void Accept(AstVisitor* v);
// Type testing & conversion
virtual UnaryOperation* AsUnaryOperation() { return this; }
Token::Value op() const { return op_; }
Expression* expression() const { return expression_; }
private:
Token::Value op_;
Expression* expression_;
};
class BinaryOperation: public Expression {
public:
BinaryOperation(Token::Value op, Expression* left, Expression* right)
: op_(op), left_(left), right_(right) {
ASSERT(Token::IsBinaryOp(op));
}
virtual void Accept(AstVisitor* v);
// Type testing & conversion
virtual BinaryOperation* AsBinaryOperation() { return this; }
// True iff the result can be safely overwritten (to avoid allocation).
// False for operations that can return one of their operands.
bool ResultOverwriteAllowed() {
switch (op_) {
case Token::COMMA:
case Token::OR:
case Token::AND:
return false;
case Token::BIT_OR:
case Token::BIT_XOR:
case Token::BIT_AND:
case Token::SHL:
case Token::SAR:
case Token::SHR:
case Token::ADD:
case Token::SUB:
case Token::MUL:
case Token::DIV:
case Token::MOD:
return true;
default:
UNREACHABLE();
}
return false;
}
Token::Value op() const { return op_; }
Expression* left() const { return left_; }
Expression* right() const { return right_; }
private:
Token::Value op_;
Expression* left_;
Expression* right_;
};
class CountOperation: public Expression {
public:
CountOperation(bool is_prefix, Token::Value op, Expression* expression)
: is_prefix_(is_prefix), op_(op), expression_(expression) {
ASSERT(Token::IsCountOp(op));
}
virtual void Accept(AstVisitor* v);
bool is_prefix() const { return is_prefix_; }
bool is_postfix() const { return !is_prefix_; }
Token::Value op() const { return op_; }
Token::Value binary_op() {
return op_ == Token::INC ? Token::ADD : Token::SUB;
}
Expression* expression() const { return expression_; }
virtual void MarkAsStatement() { is_prefix_ = true; }
private:
bool is_prefix_;
Token::Value op_;
Expression* expression_;
};
class CompareOperation: public Expression {
public:
CompareOperation(Token::Value op, Expression* left, Expression* right)
: op_(op), left_(left), right_(right), is_for_loop_condition_(false) {
ASSERT(Token::IsCompareOp(op));
}
virtual void Accept(AstVisitor* v);
Token::Value op() const { return op_; }
Expression* left() const { return left_; }
Expression* right() const { return right_; }
// Accessors for flag whether this compare operation is hanging of a for loop.
bool is_for_loop_condition() const { return is_for_loop_condition_; }
void set_is_for_loop_condition() { is_for_loop_condition_ = true; }
// Type testing & conversion
virtual CompareOperation* AsCompareOperation() { return this; }
private:
Token::Value op_;
Expression* left_;
Expression* right_;
bool is_for_loop_condition_;
};
class Conditional: public Expression {
public:
Conditional(Expression* condition,
Expression* then_expression,
Expression* else_expression)
: condition_(condition),
then_expression_(then_expression),
else_expression_(else_expression) { }
virtual void Accept(AstVisitor* v);
Expression* condition() const { return condition_; }
Expression* then_expression() const { return then_expression_; }
Expression* else_expression() const { return else_expression_; }
private:
Expression* condition_;
Expression* then_expression_;
Expression* else_expression_;
};
class Assignment: public Expression {
public:
Assignment(Token::Value op, Expression* target, Expression* value, int pos)
: op_(op), target_(target), value_(value), pos_(pos),
block_start_(false), block_end_(false) {
ASSERT(Token::IsAssignmentOp(op));
}
virtual void Accept(AstVisitor* v);
virtual Assignment* AsAssignment() { return this; }
Token::Value binary_op() const;
Token::Value op() const { return op_; }
Expression* target() const { return target_; }
Expression* value() const { return value_; }
int position() { return pos_; }
// This check relies on the definition order of token in token.h.
bool is_compound() const { return op() > Token::ASSIGN; }
// An initialization block is a series of statments of the form
// x.y.z.a = ...; x.y.z.b = ...; etc. The parser marks the beginning and
// ending of these blocks to allow for optimizations of initialization
// blocks.
bool starts_initialization_block() { return block_start_; }
bool ends_initialization_block() { return block_end_; }
void mark_block_start() { block_start_ = true; }
void mark_block_end() { block_end_ = true; }
private:
Token::Value op_;
Expression* target_;
Expression* value_;
int pos_;
bool block_start_;
bool block_end_;
};
class Throw: public Expression {
public:
Throw(Expression* exception, int pos)
: exception_(exception), pos_(pos) {}
virtual void Accept(AstVisitor* v);
Expression* exception() const { return exception_; }
int position() const { return pos_; }
private:
Expression* exception_;
int pos_;
};
class FunctionLiteral: public Expression {
public:
FunctionLiteral(Handle<String> name,
Scope* scope,
ZoneList<Statement*>* body,
int materialized_literal_count,
int expected_property_count,
bool has_only_simple_this_property_assignments,
Handle<FixedArray> this_property_assignments,
int num_parameters,
int start_position,
int end_position,
bool is_expression)
: name_(name),
scope_(scope),
body_(body),
materialized_literal_count_(materialized_literal_count),
expected_property_count_(expected_property_count),
has_only_simple_this_property_assignments_(
has_only_simple_this_property_assignments),
this_property_assignments_(this_property_assignments),
num_parameters_(num_parameters),
start_position_(start_position),
end_position_(end_position),
is_expression_(is_expression),
function_token_position_(RelocInfo::kNoPosition),
inferred_name_(Heap::empty_string()),
try_full_codegen_(false) {
#ifdef DEBUG
already_compiled_ = false;
#endif
}
virtual void Accept(AstVisitor* v);
// Type testing & conversion
virtual FunctionLiteral* AsFunctionLiteral() { return this; }
virtual bool IsLeaf() { return true; }
Handle<String> name() const { return name_; }
Scope* scope() const { return scope_; }
ZoneList<Statement*>* body() const { return body_; }
void set_function_token_position(int pos) { function_token_position_ = pos; }
int function_token_position() const { return function_token_position_; }
int start_position() const { return start_position_; }
int end_position() const { return end_position_; }
bool is_expression() const { return is_expression_; }
int materialized_literal_count() { return materialized_literal_count_; }
int expected_property_count() { return expected_property_count_; }
bool has_only_simple_this_property_assignments() {
return has_only_simple_this_property_assignments_;
}
Handle<FixedArray> this_property_assignments() {
return this_property_assignments_;
}
int num_parameters() { return num_parameters_; }
bool AllowsLazyCompilation();
Handle<String> inferred_name() const { return inferred_name_; }
void set_inferred_name(Handle<String> inferred_name) {
inferred_name_ = inferred_name;
}
bool try_full_codegen() { return try_full_codegen_; }
void set_try_full_codegen(bool flag) { try_full_codegen_ = flag; }
#ifdef DEBUG
void mark_as_compiled() {
ASSERT(!already_compiled_);
already_compiled_ = true;
}
#endif
private:
Handle<String> name_;
Scope* scope_;
ZoneList<Statement*>* body_;
int materialized_literal_count_;
int expected_property_count_;
bool has_only_simple_this_property_assignments_;
Handle<FixedArray> this_property_assignments_;
int num_parameters_;
int start_position_;
int end_position_;
bool is_expression_;
int function_token_position_;
Handle<String> inferred_name_;
bool try_full_codegen_;
#ifdef DEBUG
bool already_compiled_;
#endif
};
class FunctionBoilerplateLiteral: public Expression {
public:
explicit FunctionBoilerplateLiteral(Handle<JSFunction> boilerplate)
: boilerplate_(boilerplate) {
ASSERT(boilerplate->IsBoilerplate());
}
Handle<JSFunction> boilerplate() const { return boilerplate_; }
virtual bool IsLeaf() { return true; }
virtual void Accept(AstVisitor* v);
private:
Handle<JSFunction> boilerplate_;
};
class ThisFunction: public Expression {
public:
virtual void Accept(AstVisitor* v);
virtual bool IsLeaf() { return true; }
};
// ----------------------------------------------------------------------------
// Regular expressions
class RegExpVisitor BASE_EMBEDDED {
public:
virtual ~RegExpVisitor() { }
#define MAKE_CASE(Name) \
virtual void* Visit##Name(RegExp##Name*, void* data) = 0;
FOR_EACH_REG_EXP_TREE_TYPE(MAKE_CASE)
#undef MAKE_CASE
};
class RegExpTree: public ZoneObject {
public:
static const int kInfinity = kMaxInt;
virtual ~RegExpTree() { }
virtual void* Accept(RegExpVisitor* visitor, void* data) = 0;
virtual RegExpNode* ToNode(RegExpCompiler* compiler,
RegExpNode* on_success) = 0;
virtual bool IsTextElement() { return false; }
virtual bool IsAnchored() { return false; }
virtual int min_match() = 0;
virtual int max_match() = 0;
// Returns the interval of registers used for captures within this
// expression.
virtual Interval CaptureRegisters() { return Interval::Empty(); }
virtual void AppendToText(RegExpText* text);
SmartPointer<const char> ToString();
#define MAKE_ASTYPE(Name) \
virtual RegExp##Name* As##Name(); \
virtual bool Is##Name();
FOR_EACH_REG_EXP_TREE_TYPE(MAKE_ASTYPE)
#undef MAKE_ASTYPE
};
class RegExpDisjunction: public RegExpTree {
public:
explicit RegExpDisjunction(ZoneList<RegExpTree*>* alternatives);
virtual void* Accept(RegExpVisitor* visitor, void* data);
virtual RegExpNode* ToNode(RegExpCompiler* compiler,
RegExpNode* on_success);
virtual RegExpDisjunction* AsDisjunction();
virtual Interval CaptureRegisters();
virtual bool IsDisjunction();
virtual bool IsAnchored();
virtual int min_match() { return min_match_; }
virtual int max_match() { return max_match_; }
ZoneList<RegExpTree*>* alternatives() { return alternatives_; }
private:
ZoneList<RegExpTree*>* alternatives_;
int min_match_;
int max_match_;
};
class RegExpAlternative: public RegExpTree {
public:
explicit RegExpAlternative(ZoneList<RegExpTree*>* nodes);
virtual void* Accept(RegExpVisitor* visitor, void* data);
virtual RegExpNode* ToNode(RegExpCompiler* compiler,
RegExpNode* on_success);
virtual RegExpAlternative* AsAlternative();
virtual Interval CaptureRegisters();
virtual bool IsAlternative();
virtual bool IsAnchored();
virtual int min_match() { return min_match_; }
virtual int max_match() { return max_match_; }
ZoneList<RegExpTree*>* nodes() { return nodes_; }
private:
ZoneList<RegExpTree*>* nodes_;
int min_match_;
int max_match_;
};
class RegExpAssertion: public RegExpTree {
public:
enum Type {
START_OF_LINE,
START_OF_INPUT,
END_OF_LINE,
END_OF_INPUT,
BOUNDARY,
NON_BOUNDARY
};
explicit RegExpAssertion(Type type) : type_(type) { }
virtual void* Accept(RegExpVisitor* visitor, void* data);
virtual RegExpNode* ToNode(RegExpCompiler* compiler,
RegExpNode* on_success);
virtual RegExpAssertion* AsAssertion();
virtual bool IsAssertion();
virtual bool IsAnchored();
virtual int min_match() { return 0; }
virtual int max_match() { return 0; }
Type type() { return type_; }
private:
Type type_;
};
class CharacterSet BASE_EMBEDDED {
public:
explicit CharacterSet(uc16 standard_set_type)
: ranges_(NULL),
standard_set_type_(standard_set_type) {}
explicit CharacterSet(ZoneList<CharacterRange>* ranges)
: ranges_(ranges),
standard_set_type_(0) {}
ZoneList<CharacterRange>* ranges();
uc16 standard_set_type() { return standard_set_type_; }
void set_standard_set_type(uc16 special_set_type) {
standard_set_type_ = special_set_type;
}
bool is_standard() { return standard_set_type_ != 0; }
void Canonicalize();
private:
ZoneList<CharacterRange>* ranges_;
// If non-zero, the value represents a standard set (e.g., all whitespace
// characters) without having to expand the ranges.
uc16 standard_set_type_;
};
class RegExpCharacterClass: public RegExpTree {
public:
RegExpCharacterClass(ZoneList<CharacterRange>* ranges, bool is_negated)
: set_(ranges),
is_negated_(is_negated) { }
explicit RegExpCharacterClass(uc16 type)
: set_(type),
is_negated_(false) { }
virtual void* Accept(RegExpVisitor* visitor, void* data);
virtual RegExpNode* ToNode(RegExpCompiler* compiler,
RegExpNode* on_success);
virtual RegExpCharacterClass* AsCharacterClass();
virtual bool IsCharacterClass();
virtual bool IsTextElement() { return true; }
virtual int min_match() { return 1; }
virtual int max_match() { return 1; }
virtual void AppendToText(RegExpText* text);
CharacterSet character_set() { return set_; }
// TODO(lrn): Remove need for complex version if is_standard that
// recognizes a mangled standard set and just do { return set_.is_special(); }
bool is_standard();
// Returns a value representing the standard character set if is_standard()
// returns true.
// Currently used values are:
// s : unicode whitespace
// S : unicode non-whitespace
// w : ASCII word character (digit, letter, underscore)
// W : non-ASCII word character
// d : ASCII digit
// D : non-ASCII digit
// . : non-unicode non-newline
// * : All characters
uc16 standard_type() { return set_.standard_set_type(); }
ZoneList<CharacterRange>* ranges() { return set_.ranges(); }
bool is_negated() { return is_negated_; }
private:
CharacterSet set_;
bool is_negated_;
};
class RegExpAtom: public RegExpTree {
public:
explicit RegExpAtom(Vector<const uc16> data) : data_(data) { }
virtual void* Accept(RegExpVisitor* visitor, void* data);
virtual RegExpNode* ToNode(RegExpCompiler* compiler,
RegExpNode* on_success);
virtual RegExpAtom* AsAtom();
virtual bool IsAtom();
virtual bool IsTextElement() { return true; }
virtual int min_match() { return data_.length(); }
virtual int max_match() { return data_.length(); }
virtual void AppendToText(RegExpText* text);
Vector<const uc16> data() { return data_; }
int length() { return data_.length(); }
private:
Vector<const uc16> data_;
};
class RegExpText: public RegExpTree {
public:
RegExpText() : elements_(2), length_(0) {}
virtual void* Accept(RegExpVisitor* visitor, void* data);
virtual RegExpNode* ToNode(RegExpCompiler* compiler,
RegExpNode* on_success);
virtual RegExpText* AsText();
virtual bool IsText();
virtual bool IsTextElement() { return true; }
virtual int min_match() { return length_; }
virtual int max_match() { return length_; }
virtual void AppendToText(RegExpText* text);
void AddElement(TextElement elm) {
elements_.Add(elm);
length_ += elm.length();
};
ZoneList<TextElement>* elements() { return &elements_; }
private:
ZoneList<TextElement> elements_;
int length_;
};
class RegExpQuantifier: public RegExpTree {
public:
enum Type { GREEDY, NON_GREEDY, POSSESSIVE };
RegExpQuantifier(int min, int max, Type type, RegExpTree* body)
: body_(body),
min_(min),
max_(max),
min_match_(min * body->min_match()),
type_(type) {
if (max > 0 && body->max_match() > kInfinity / max) {
max_match_ = kInfinity;
} else {
max_match_ = max * body->max_match();
}
}
virtual void* Accept(RegExpVisitor* visitor, void* data);
virtual RegExpNode* ToNode(RegExpCompiler* compiler,
RegExpNode* on_success);
static RegExpNode* ToNode(int min,
int max,
bool is_greedy,
RegExpTree* body,
RegExpCompiler* compiler,
RegExpNode* on_success,
bool not_at_start = false);
virtual RegExpQuantifier* AsQuantifier();
virtual Interval CaptureRegisters();
virtual bool IsQuantifier();
virtual int min_match() { return min_match_; }
virtual int max_match() { return max_match_; }
int min() { return min_; }
int max() { return max_; }
bool is_possessive() { return type_ == POSSESSIVE; }
bool is_non_greedy() { return type_ == NON_GREEDY; }
bool is_greedy() { return type_ == GREEDY; }
RegExpTree* body() { return body_; }
private:
RegExpTree* body_;
int min_;
int max_;
int min_match_;
int max_match_;
Type type_;
};
class RegExpCapture: public RegExpTree {
public:
explicit RegExpCapture(RegExpTree* body, int index)
: body_(body), index_(index) { }
virtual void* Accept(RegExpVisitor* visitor, void* data);
virtual RegExpNode* ToNode(RegExpCompiler* compiler,
RegExpNode* on_success);
static RegExpNode* ToNode(RegExpTree* body,
int index,
RegExpCompiler* compiler,
RegExpNode* on_success);
virtual RegExpCapture* AsCapture();
virtual bool IsAnchored();
virtual Interval CaptureRegisters();
virtual bool IsCapture();
virtual int min_match() { return body_->min_match(); }
virtual int max_match() { return body_->max_match(); }
RegExpTree* body() { return body_; }
int index() { return index_; }
static int StartRegister(int index) { return index * 2; }
static int EndRegister(int index) { return index * 2 + 1; }
private:
RegExpTree* body_;
int index_;
};
class RegExpLookahead: public RegExpTree {
public:
RegExpLookahead(RegExpTree* body,
bool is_positive,
int capture_count,
int capture_from)
: body_(body),
is_positive_(is_positive),
capture_count_(capture_count),
capture_from_(capture_from) { }
virtual void* Accept(RegExpVisitor* visitor, void* data);
virtual RegExpNode* ToNode(RegExpCompiler* compiler,
RegExpNode* on_success);
virtual RegExpLookahead* AsLookahead();
virtual Interval CaptureRegisters();
virtual bool IsLookahead();
virtual bool IsAnchored();
virtual int min_match() { return 0; }
virtual int max_match() { return 0; }
RegExpTree* body() { return body_; }
bool is_positive() { return is_positive_; }
int capture_count() { return capture_count_; }
int capture_from() { return capture_from_; }
private:
RegExpTree* body_;
bool is_positive_;
int capture_count_;
int capture_from_;
};
class RegExpBackReference: public RegExpTree {
public:
explicit RegExpBackReference(RegExpCapture* capture)
: capture_(capture) { }
virtual void* Accept(RegExpVisitor* visitor, void* data);
virtual RegExpNode* ToNode(RegExpCompiler* compiler,
RegExpNode* on_success);
virtual RegExpBackReference* AsBackReference();
virtual bool IsBackReference();
virtual int min_match() { return 0; }
virtual int max_match() { return capture_->max_match(); }
int index() { return capture_->index(); }
RegExpCapture* capture() { return capture_; }
private:
RegExpCapture* capture_;
};
class RegExpEmpty: public RegExpTree {
public:
RegExpEmpty() { }
virtual void* Accept(RegExpVisitor* visitor, void* data);
virtual RegExpNode* ToNode(RegExpCompiler* compiler,
RegExpNode* on_success);
virtual RegExpEmpty* AsEmpty();
virtual bool IsEmpty();
virtual int min_match() { return 0; }
virtual int max_match() { return 0; }
static RegExpEmpty* GetInstance() { return &kInstance; }
private:
static RegExpEmpty kInstance;
};
// ----------------------------------------------------------------------------
// Basic visitor
// - leaf node visitors are abstract.
class AstVisitor BASE_EMBEDDED {
public:
AstVisitor() : stack_overflow_(false) { }
virtual ~AstVisitor() { }
// Dispatch
void Visit(AstNode* node) { node->Accept(this); }
// Iteration
virtual void VisitDeclarations(ZoneList<Declaration*>* declarations);
virtual void VisitStatements(ZoneList<Statement*>* statements);
virtual void VisitExpressions(ZoneList<Expression*>* expressions);
// Stack overflow tracking support.
bool HasStackOverflow() const { return stack_overflow_; }
bool CheckStackOverflow() {
if (stack_overflow_) return true;
StackLimitCheck check;
if (!check.HasOverflowed()) return false;
return (stack_overflow_ = true);
}
// If a stack-overflow exception is encountered when visiting a
// node, calling SetStackOverflow will make sure that the visitor
// bails out without visiting more nodes.
void SetStackOverflow() { stack_overflow_ = true; }
// Individual nodes
#define DEF_VISIT(type) \
virtual void Visit##type(type* node) = 0;
AST_NODE_LIST(DEF_VISIT)
#undef DEF_VISIT
private:
bool stack_overflow_;
};
} } // namespace v8::internal
#endif // V8_AST_H_