[parser] Refactor AstTraversalVisitor

src/ast/ast-traversal-visitor.h

Index: src/ast/ast-traversal-visitor.h
diff --git a/src/ast/ast-traversal-visitor.h b/src/ast/ast-traversal-visitor.h
new file mode 100644
index 0000000000000000000000000000000000000000..c8284b771e7b8de9df0b7c52652524c54974b97d
--- /dev/null
+++ b/src/ast/ast-traversal-visitor.h
@@ -0,0 +1,504 @@
+// Copyright 2016 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef V8_AST_AST_TRAVERSAL_VISITOR_H_
+#define V8_AST_AST_TRAVERSAL_VISITOR_H_
+
+#include "src/ast/ast.h"
+#include "src/ast/scopes.h"
+
+namespace v8 {
+namespace internal {
+
+// ----------------------------------------------------------------------------
+// Traversal visitor
+// - fully traverses the entire AST.
+//
+// Sub-class should parametrize AstTraversalVisitor with itself, e.g.:
+//   class SpecificVisitor : public AstTraversalVisitor<SpecificVisitor> { ... }
+//
+// It invokes VisitNode on each AST node, before proceeding with its subtrees.
+// It invokes VisitExpression (after VisitNode) on each AST node that is an
+// expression, before proceeding with its subtrees.
+// It proceeds with the subtrees only if these two methods return true.
+// Sub-classes may override VisitNode and VisitExpressions, whose implementation
+// is dummy here.  Or they may override the specific Visit* methods.
+
+template <class Subclass>
+class AstTraversalVisitor : public AstVisitor<Subclass> {
+ public:
+  explicit AstTraversalVisitor(Isolate* isolate, AstNode* root = nullptr);
+  explicit AstTraversalVisitor(uintptr_t stack_limit, AstNode* root = nullptr);
+
+  void Run() {
+    DCHECK_NOT_NULL(root_);
+    Visit(root_);
+  }
+
+  bool VisitNode(AstNode* node) { return true; }
+  bool VisitExpression(Expression* node) { return true; }
+
+  // Iteration left-to-right.
+  void VisitDeclarations(ZoneList<Declaration*>* declarations);
+  void VisitStatements(ZoneList<Statement*>* statements);
+
+// Individual nodes
+#define DECLARE_VISIT(type) void Visit##type(type* node);
+  AST_NODE_LIST(DECLARE_VISIT)
+#undef DECLARE_VISIT
+
+ protected:
+  int depth() const { return depth_; }
+
+ private:
+  DEFINE_AST_VISITOR_SUBCLASS_MEMBERS();
+
+  AstNode* root_;
+  int depth_;
+
+  DISALLOW_COPY_AND_ASSIGN(AstTraversalVisitor);
+};
+
+// ----------------------------------------------------------------------------
+// Implementation of AstTraversalVisitor
+
+#define PROCESS_NODE(node) do {                         \
+    if (!(this->impl()->VisitNode(node))) return;       \
+  } while (false)
+
+#define PROCESS_EXPRESSION(node) do {                           \
+    PROCESS_NODE(node);                                         \
+    if (!(this->impl()->VisitExpression(node))) return;         \
+  } while (false)
+
+#define RECURSE(call)               \
+  do {                              \
+    DCHECK(!HasStackOverflow());    \
+    this->impl()->call;             \
+    if (HasStackOverflow()) return; \
+  } while (false)
+
+#define RECURSE_EXPRESSION(call)    \
+  do {                              \
+    DCHECK(!HasStackOverflow());    \
+    ++depth_;                       \
+    this->impl()->call;             \
+    --depth_;                       \
+    if (HasStackOverflow()) return; \
+  } while (false)
+
+template <class Subclass>
+AstTraversalVisitor<Subclass>::AstTraversalVisitor(Isolate* isolate,
+                                                   AstNode* root)
+    : root_(root), depth_(0) {
+  InitializeAstVisitor(isolate);
+}
+
+template <class Subclass>
+AstTraversalVisitor<Subclass>::AstTraversalVisitor(uintptr_t stack_limit,
+                                                   AstNode* root)
+    : root_(root), depth_(0) {
+  InitializeAstVisitor(stack_limit);
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitDeclarations(
+    ZoneList<Declaration*>* decls) {
+  for (int i = 0; i < decls->length(); ++i) {
+    Declaration* decl = decls->at(i);
+    RECURSE(Visit(decl));
+  }
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitStatements(
+    ZoneList<Statement*>* stmts) {
+  for (int i = 0; i < stmts->length(); ++i) {
+    Statement* stmt = stmts->at(i);
+    RECURSE(Visit(stmt));
+    if (stmt->IsJump()) break;
+  }
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitVariableDeclaration(
+    VariableDeclaration* decl) {
+  PROCESS_NODE(decl);
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitFunctionDeclaration(
+    FunctionDeclaration* decl) {
+  PROCESS_NODE(decl);
+  RECURSE(Visit(decl->fun()));
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitBlock(Block* stmt) {
+  PROCESS_NODE(stmt);
+  RECURSE(VisitStatements(stmt->statements()));
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitExpressionStatement(
+    ExpressionStatement* stmt) {
+  PROCESS_NODE(stmt);
+  RECURSE(Visit(stmt->expression()));
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitEmptyStatement(EmptyStatement* stmt) {}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitSloppyBlockFunctionStatement(
+    SloppyBlockFunctionStatement* stmt) {
+  PROCESS_NODE(stmt);
+  RECURSE(Visit(stmt->statement()));
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitIfStatement(IfStatement* stmt) {
+  PROCESS_NODE(stmt);
+  RECURSE(Visit(stmt->condition()));
+  RECURSE(Visit(stmt->then_statement()));
+  RECURSE(Visit(stmt->else_statement()));
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitContinueStatement(
+    ContinueStatement* stmt) {
+  PROCESS_NODE(stmt);
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitBreakStatement(BreakStatement* stmt) {
+  PROCESS_NODE(stmt);
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitReturnStatement(
+    ReturnStatement* stmt) {
+  PROCESS_NODE(stmt);
+  RECURSE(Visit(stmt->expression()));
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitWithStatement(WithStatement* stmt) {
+  PROCESS_NODE(stmt);
+  RECURSE(Visit(stmt->expression()));
+  RECURSE(Visit(stmt->statement()));
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitSwitchStatement(
+    SwitchStatement* stmt) {
+  PROCESS_NODE(stmt);
+  RECURSE(Visit(stmt->tag()));
+
+  ZoneList<CaseClause*>* clauses = stmt->cases();
+  for (int i = 0; i < clauses->length(); ++i) {
+    CaseClause* clause = clauses->at(i);
+    if (!clause->is_default()) {
+      Expression* label = clause->label();
+      RECURSE(Visit(label));
+    }
+    ZoneList<Statement*>* stmts = clause->statements();
+    RECURSE(VisitStatements(stmts));
+  }
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitCaseClause(CaseClause* clause) {
+  UNREACHABLE();
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitDoWhileStatement(
+    DoWhileStatement* stmt) {
+  PROCESS_NODE(stmt);
+  RECURSE(Visit(stmt->body()));
+  RECURSE(Visit(stmt->cond()));
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitWhileStatement(WhileStatement* stmt) {
+  PROCESS_NODE(stmt);
+  RECURSE(Visit(stmt->cond()));
+  RECURSE(Visit(stmt->body()));
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitForStatement(ForStatement* stmt) {
+  PROCESS_NODE(stmt);
+  if (stmt->init() != NULL) {
+    RECURSE(Visit(stmt->init()));
+  }
+  if (stmt->cond() != NULL) {
+    RECURSE(Visit(stmt->cond()));
+  }
+  if (stmt->next() != NULL) {
+    RECURSE(Visit(stmt->next()));
+  }
+  RECURSE(Visit(stmt->body()));
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitForInStatement(ForInStatement* stmt) {
+  PROCESS_NODE(stmt);
+  RECURSE(Visit(stmt->enumerable()));
+  RECURSE(Visit(stmt->body()));
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitForOfStatement(ForOfStatement* stmt) {
+  PROCESS_NODE(stmt);
+  RECURSE(Visit(stmt->assign_iterator()));
+  RECURSE(Visit(stmt->next_result()));
+  RECURSE(Visit(stmt->result_done()));
+  RECURSE(Visit(stmt->assign_each()));
+  RECURSE(Visit(stmt->body()));
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitTryCatchStatement(
+    TryCatchStatement* stmt) {
+  PROCESS_NODE(stmt);
+  RECURSE(Visit(stmt->try_block()));
+  RECURSE(Visit(stmt->catch_block()));
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitTryFinallyStatement(
+    TryFinallyStatement* stmt) {
+  PROCESS_NODE(stmt);
+  RECURSE(Visit(stmt->try_block()));
+  RECURSE(Visit(stmt->finally_block()));
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitDebuggerStatement(
+    DebuggerStatement* stmt) {
+  PROCESS_NODE(stmt);
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitFunctionLiteral(
+    FunctionLiteral* expr) {
+  PROCESS_EXPRESSION(expr);
+  Scope* scope = expr->scope();
+  RECURSE_EXPRESSION(VisitDeclarations(scope->declarations()));
+  RECURSE_EXPRESSION(VisitStatements(expr->body()));
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitNativeFunctionLiteral(
+    NativeFunctionLiteral* expr) {
+  PROCESS_EXPRESSION(expr);
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitDoExpression(DoExpression* expr) {
+  PROCESS_EXPRESSION(expr);
+  RECURSE(VisitBlock(expr->block()));
+  RECURSE(VisitVariableProxy(expr->result()));
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitConditional(Conditional* expr) {
+  PROCESS_EXPRESSION(expr);
+  RECURSE_EXPRESSION(Visit(expr->condition()));
+  RECURSE_EXPRESSION(Visit(expr->then_expression()));
+  RECURSE_EXPRESSION(Visit(expr->else_expression()));
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitVariableProxy(VariableProxy* expr) {
+  PROCESS_EXPRESSION(expr);
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitLiteral(Literal* expr) {
+  PROCESS_EXPRESSION(expr);
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitRegExpLiteral(RegExpLiteral* expr) {
+  PROCESS_EXPRESSION(expr);
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitObjectLiteral(ObjectLiteral* expr) {
+  PROCESS_EXPRESSION(expr);
+  ZoneList<ObjectLiteralProperty*>* props = expr->properties();
+  for (int i = 0; i < props->length(); ++i) {
+    ObjectLiteralProperty* prop = props->at(i);
+    RECURSE_EXPRESSION(Visit(prop->key()));
+    RECURSE_EXPRESSION(Visit(prop->value()));
+  }
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitArrayLiteral(ArrayLiteral* expr) {
+  PROCESS_EXPRESSION(expr);
+  ZoneList<Expression*>* values = expr->values();
+  for (int i = 0; i < values->length(); ++i) {
+    Expression* value = values->at(i);
+    RECURSE_EXPRESSION(Visit(value));
+  }
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitAssignment(Assignment* expr) {
+  PROCESS_EXPRESSION(expr);
+  RECURSE_EXPRESSION(Visit(expr->target()));
+  RECURSE_EXPRESSION(Visit(expr->value()));
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitYield(Yield* expr) {
+  PROCESS_EXPRESSION(expr);
+  RECURSE_EXPRESSION(Visit(expr->generator_object()));
+  RECURSE_EXPRESSION(Visit(expr->expression()));
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitThrow(Throw* expr) {
+  PROCESS_EXPRESSION(expr);
+  RECURSE_EXPRESSION(Visit(expr->exception()));
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitProperty(Property* expr) {
+  PROCESS_EXPRESSION(expr);
+  RECURSE_EXPRESSION(Visit(expr->obj()));
+  RECURSE_EXPRESSION(Visit(expr->key()));
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitCall(Call* expr) {
+  PROCESS_EXPRESSION(expr);
+  RECURSE_EXPRESSION(Visit(expr->expression()));
+  ZoneList<Expression*>* args = expr->arguments();
+  for (int i = 0; i < args->length(); ++i) {
+    Expression* arg = args->at(i);
+    RECURSE_EXPRESSION(Visit(arg));
+  }
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitCallNew(CallNew* expr) {
+  PROCESS_EXPRESSION(expr);
+  RECURSE_EXPRESSION(Visit(expr->expression()));
+  ZoneList<Expression*>* args = expr->arguments();
+  for (int i = 0; i < args->length(); ++i) {
+    Expression* arg = args->at(i);
+    RECURSE_EXPRESSION(Visit(arg));
+  }
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitCallRuntime(CallRuntime* expr) {
+  PROCESS_EXPRESSION(expr);
+  ZoneList<Expression*>* args = expr->arguments();
+  for (int i = 0; i < args->length(); ++i) {
+    Expression* arg = args->at(i);
+    RECURSE_EXPRESSION(Visit(arg));
+  }
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitUnaryOperation(UnaryOperation* expr) {
+  PROCESS_EXPRESSION(expr);
+  RECURSE_EXPRESSION(Visit(expr->expression()));
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitCountOperation(CountOperation* expr) {
+  PROCESS_EXPRESSION(expr);
+  RECURSE_EXPRESSION(Visit(expr->expression()));
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitBinaryOperation(
+    BinaryOperation* expr) {
+  PROCESS_EXPRESSION(expr);
+  RECURSE_EXPRESSION(Visit(expr->left()));
+  RECURSE_EXPRESSION(Visit(expr->right()));
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitCompareOperation(
+    CompareOperation* expr) {
+  PROCESS_EXPRESSION(expr);
+  RECURSE_EXPRESSION(Visit(expr->left()));
+  RECURSE_EXPRESSION(Visit(expr->right()));
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitThisFunction(ThisFunction* expr) {
+  PROCESS_EXPRESSION(expr);
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitClassLiteral(ClassLiteral* expr) {
+  PROCESS_EXPRESSION(expr);
+  if (expr->extends() != nullptr) {
+    RECURSE_EXPRESSION(Visit(expr->extends()));
+  }
+  RECURSE_EXPRESSION(Visit(expr->constructor()));
+  ZoneList<ObjectLiteralProperty*>* props = expr->properties();
+  for (int i = 0; i < props->length(); ++i) {
+    ObjectLiteralProperty* prop = props->at(i);
+    if (!prop->key()->IsLiteral()) {
+      RECURSE_EXPRESSION(Visit(prop->key()));
+    }
+    RECURSE_EXPRESSION(Visit(prop->value()));
+  }
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitSpread(Spread* expr) {
+  PROCESS_EXPRESSION(expr);
+  RECURSE_EXPRESSION(Visit(expr->expression()));
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitEmptyParentheses(
+    EmptyParentheses* expr) {
+  PROCESS_EXPRESSION(expr);
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitSuperPropertyReference(
+    SuperPropertyReference* expr) {
+  PROCESS_EXPRESSION(expr);
+  RECURSE_EXPRESSION(VisitVariableProxy(expr->this_var()));
+  RECURSE_EXPRESSION(Visit(expr->home_object()));
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitSuperCallReference(
+    SuperCallReference* expr) {
+  PROCESS_EXPRESSION(expr);
+  RECURSE_EXPRESSION(VisitVariableProxy(expr->this_var()));
+  RECURSE_EXPRESSION(VisitVariableProxy(expr->new_target_var()));
+  RECURSE_EXPRESSION(VisitVariableProxy(expr->this_function_var()));
+}
+
+template <class Subclass>
+void AstTraversalVisitor<Subclass>::VisitRewritableExpression(
+    RewritableExpression* expr) {
+  PROCESS_EXPRESSION(expr);
+  RECURSE(Visit(expr->expression()));
+}
+
+#undef PROCESS_NODE
+#undef PROCESS_EXPRESSION
+#undef RECURSE_EXPRESSION
+#undef RECURSE
+
+}  // namespace internal
+}  // namespace v8
+
+#endif  // V8_AST_AST_TRAVERSAL_VISITOR_H_