Add a generic mechanism for expression rewriting

src/ast/ast-expression-rewriter.cc

Index: src/ast/ast-expression-rewriter.cc
diff --git a/src/ast/ast-expression-rewriter.cc b/src/ast/ast-expression-rewriter.cc
new file mode 100644
index 0000000000000000000000000000000000000000..49cc7f6ff4df6ccf4f27e40c369750df949b74c6
--- /dev/null
+++ b/src/ast/ast-expression-rewriter.cc
@@ -0,0 +1,409 @@
+// Copyright 2015 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.
+
+#include "src/ast/ast.h"
+#include "src/ast/ast-expression-rewriter.h"
+
+namespace v8 {
+namespace internal {
+
+// ----------------------------------------------------------------------------
+// Implementation of AstExpressionRewriter
+// The AST is traversed but no actual rewriting takes place, unless the
+// Visit methods are overriden in subclasses.
+
+#define REWRITE_THIS(node)                \
+  do {                                    \
+    if (!RewriteExpression(node)) return; \
+  } while (false)
+#define NOTHING() DCHECK_NULL(replacement_)
+
+
+void AstExpressionRewriter::VisitDeclarations(
+    ZoneList<Declaration*>* declarations) {
+  for (int i = 0; i < declarations->length(); i++) {
+    AST_REWRITE_LIST_ELEMENT(Declaration, declarations, i);
+  }
+}
+
+
+void AstExpressionRewriter::VisitStatements(ZoneList<Statement*>* statements) {
+  for (int i = 0; i < statements->length(); i++) {
+    AST_REWRITE_LIST_ELEMENT(Statement, statements, i);
+    // Not stopping when a jump statement is found.
+  }
+}
+
+
+void AstExpressionRewriter::VisitExpressions(
+    ZoneList<Expression*>* expressions) {
+  for (int i = 0; i < expressions->length(); i++) {
+    // The variable statement visiting code may pass NULL expressions
+    // to this code. Maybe this should be handled by introducing an
+    // undefined expression or literal?  Revisit this code if this
+    // changes
+    if (expressions->at(i) != nullptr) {
+      AST_REWRITE_LIST_ELEMENT(Expression, expressions, i);
+    }
+  }
+}
+
+
+void AstExpressionRewriter::VisitVariableDeclaration(
+    VariableDeclaration* node) {
+  // Not visiting `proxy_`.
+  NOTHING();
+}
+
+
+void AstExpressionRewriter::VisitFunctionDeclaration(
+    FunctionDeclaration* node) {
+  // Not visiting `proxy_`.
+  AST_REWRITE_PROPERTY(FunctionLiteral, node, fun);
+}
+
+
+void AstExpressionRewriter::VisitImportDeclaration(ImportDeclaration* node) {
+  // Not visiting `proxy_`.
+  NOTHING();
+}
+
+
+void AstExpressionRewriter::VisitExportDeclaration(ExportDeclaration* node) {
+  // Not visiting `proxy_`.
+  NOTHING();
+}
+
+
+void AstExpressionRewriter::VisitBlock(Block* node) {
+  VisitStatements(node->statements());
+}
+
+
+void AstExpressionRewriter::VisitExpressionStatement(
+    ExpressionStatement* node) {
+  AST_REWRITE_PROPERTY(Expression, node, expression);
+}
+
+
+void AstExpressionRewriter::VisitEmptyStatement(EmptyStatement* node) {
+  NOTHING();
+}
+
+
+void AstExpressionRewriter::VisitSloppyBlockFunctionStatement(
+    SloppyBlockFunctionStatement* node) {
+  AST_REWRITE_PROPERTY(Statement, node, statement);
+}
+
+
+void AstExpressionRewriter::VisitIfStatement(IfStatement* node) {
+  AST_REWRITE_PROPERTY(Expression, node, condition);
+  AST_REWRITE_PROPERTY(Statement, node, then_statement);
+  AST_REWRITE_PROPERTY(Statement, node, else_statement);
+}
+
+
+void AstExpressionRewriter::VisitContinueStatement(ContinueStatement* node) {
+  NOTHING();
+}
+
+
+void AstExpressionRewriter::VisitBreakStatement(BreakStatement* node) {
+  NOTHING();
+}
+
+
+void AstExpressionRewriter::VisitReturnStatement(ReturnStatement* node) {
+  AST_REWRITE_PROPERTY(Expression, node, expression);
+}
+
+
+void AstExpressionRewriter::VisitWithStatement(WithStatement* node) {
+  AST_REWRITE_PROPERTY(Expression, node, expression);
+  AST_REWRITE_PROPERTY(Statement, node, statement);
+}
+
+
+void AstExpressionRewriter::VisitSwitchStatement(SwitchStatement* node) {
+  AST_REWRITE_PROPERTY(Expression, node, tag);
+  ZoneList<CaseClause*>* clauses = node->cases();
+  for (int i = 0; i < clauses->length(); i++) {
+    AST_REWRITE_LIST_ELEMENT(CaseClause, clauses, i);
+  }
+}
+
+
+void AstExpressionRewriter::VisitDoWhileStatement(DoWhileStatement* node) {
+  AST_REWRITE_PROPERTY(Expression, node, cond);
+  AST_REWRITE_PROPERTY(Statement, node, body);
+}
+
+
+void AstExpressionRewriter::VisitWhileStatement(WhileStatement* node) {
+  AST_REWRITE_PROPERTY(Expression, node, cond);
+  AST_REWRITE_PROPERTY(Statement, node, body);
+}
+
+
+void AstExpressionRewriter::VisitForStatement(ForStatement* node) {
+  if (node->init() != nullptr) {
+    AST_REWRITE_PROPERTY(Statement, node, init);
+  }
+  if (node->cond() != nullptr) {
+    AST_REWRITE_PROPERTY(Expression, node, cond);
+  }
+  if (node->next() != nullptr) {
+    AST_REWRITE_PROPERTY(Statement, node, next);
+  }
+  AST_REWRITE_PROPERTY(Statement, node, body);
+}
+
+
+void AstExpressionRewriter::VisitForInStatement(ForInStatement* node) {
+  AST_REWRITE_PROPERTY(Expression, node, each);
+  AST_REWRITE_PROPERTY(Expression, node, subject);
+  AST_REWRITE_PROPERTY(Statement, node, body);
+}
+
+
+void AstExpressionRewriter::VisitForOfStatement(ForOfStatement* node) {
+  AST_REWRITE_PROPERTY(Expression, node, each);
+  AST_REWRITE_PROPERTY(Expression, node, assign_iterator);
+  AST_REWRITE_PROPERTY(Expression, node, next_result);
+  AST_REWRITE_PROPERTY(Expression, node, result_done);
+  AST_REWRITE_PROPERTY(Expression, node, assign_each);
+  AST_REWRITE_PROPERTY(Expression, node, subject);
+  AST_REWRITE_PROPERTY(Statement, node, body);
+}
+
+
+void AstExpressionRewriter::VisitTryCatchStatement(TryCatchStatement* node) {
+  AST_REWRITE_PROPERTY(Block, node, try_block);
+  // Not visiting the variable.
+  AST_REWRITE_PROPERTY(Block, node, catch_block);
+}
+
+
+void AstExpressionRewriter::VisitTryFinallyStatement(
+    TryFinallyStatement* node) {
+  AST_REWRITE_PROPERTY(Block, node, try_block);
+  AST_REWRITE_PROPERTY(Block, node, finally_block);
+}
+
+
+void AstExpressionRewriter::VisitDebuggerStatement(DebuggerStatement* node) {
+  NOTHING();
+}
+
+
+void AstExpressionRewriter::VisitFunctionLiteral(FunctionLiteral* node) {
+  REWRITE_THIS(node);
+  VisitDeclarations(node->scope()->declarations());
+  ZoneList<Statement*>* body = node->body();
+  if (body != nullptr) VisitStatements(body);
+}
+
+
+void AstExpressionRewriter::VisitClassLiteral(ClassLiteral* node) {
+  REWRITE_THIS(node);
+  // Not visiting `class_variable_proxy_`.
+  if (node->extends() != nullptr) {
+    AST_REWRITE_PROPERTY(Expression, node, extends);
+  }
+  AST_REWRITE_PROPERTY(FunctionLiteral, node, constructor);
+  ZoneList<typename ClassLiteral::Property*>* properties = node->properties();
+  for (int i = 0; i < properties->length(); i++) {
+    VisitObjectLiteralProperty(properties->at(i));
+  }
+}
+
+
+void AstExpressionRewriter::VisitNativeFunctionLiteral(
+    NativeFunctionLiteral* node) {
+  REWRITE_THIS(node);
+  NOTHING();
+}
+
+
+void AstExpressionRewriter::VisitConditional(Conditional* node) {
+  REWRITE_THIS(node);
+  AST_REWRITE_PROPERTY(Expression, node, condition);
+  AST_REWRITE_PROPERTY(Expression, node, then_expression);
+  AST_REWRITE_PROPERTY(Expression, node, else_expression);
+}
+
+
+void AstExpressionRewriter::VisitVariableProxy(VariableProxy* node) {
+  REWRITE_THIS(node);
+  NOTHING();
+}
+
+
+void AstExpressionRewriter::VisitLiteral(Literal* node) {
+  REWRITE_THIS(node);
+  NOTHING();
+}
+
+
+void AstExpressionRewriter::VisitRegExpLiteral(RegExpLiteral* node) {
+  REWRITE_THIS(node);
+  NOTHING();
+}
+
+
+void AstExpressionRewriter::VisitObjectLiteral(ObjectLiteral* node) {
+  REWRITE_THIS(node);
+  ZoneList<typename ObjectLiteral::Property*>* properties = node->properties();
+  for (int i = 0; i < properties->length(); i++) {
+    VisitObjectLiteralProperty(properties->at(i));
+  }
+}
+
+
+void AstExpressionRewriter::VisitObjectLiteralProperty(
+    ObjectLiteralProperty* property) {
+  if (property == nullptr) return;
+  AST_REWRITE_PROPERTY(Expression, property, key);
+  AST_REWRITE_PROPERTY(Expression, property, value);
+}
+
+
+void AstExpressionRewriter::VisitArrayLiteral(ArrayLiteral* node) {
+  REWRITE_THIS(node);
+  VisitExpressions(node->values());
+}
+
+
+void AstExpressionRewriter::VisitAssignment(Assignment* node) {
+  REWRITE_THIS(node);
+  AST_REWRITE_PROPERTY(Expression, node, target);
+  AST_REWRITE_PROPERTY(Expression, node, value);
+}
+
+
+void AstExpressionRewriter::VisitYield(Yield* node) {
+  REWRITE_THIS(node);
+  AST_REWRITE_PROPERTY(Expression, node, generator_object);
+  AST_REWRITE_PROPERTY(Expression, node, expression);
+}
+
+
+void AstExpressionRewriter::VisitThrow(Throw* node) {
+  REWRITE_THIS(node);
+  AST_REWRITE_PROPERTY(Expression, node, exception);
+}
+
+
+void AstExpressionRewriter::VisitProperty(Property* node) {
+  REWRITE_THIS(node);
+  if (node == nullptr) return;
+  AST_REWRITE_PROPERTY(Expression, node, obj);
+  AST_REWRITE_PROPERTY(Expression, node, key);
+}
+
+
+void AstExpressionRewriter::VisitCall(Call* node) {
+  REWRITE_THIS(node);
+  AST_REWRITE_PROPERTY(Expression, node, expression);
+  VisitExpressions(node->arguments());
+}
+
+
+void AstExpressionRewriter::VisitCallNew(CallNew* node) {
+  REWRITE_THIS(node);
+  AST_REWRITE_PROPERTY(Expression, node, expression);
+  VisitExpressions(node->arguments());
+}
+
+
+void AstExpressionRewriter::VisitCallRuntime(CallRuntime* node) {
+  REWRITE_THIS(node);
+  VisitExpressions(node->arguments());
+}
+
+
+void AstExpressionRewriter::VisitUnaryOperation(UnaryOperation* node) {
+  REWRITE_THIS(node);
+  AST_REWRITE_PROPERTY(Expression, node, expression);
+}
+
+
+void AstExpressionRewriter::VisitCountOperation(CountOperation* node) {
+  REWRITE_THIS(node);
+  AST_REWRITE_PROPERTY(Expression, node, expression);
+}
+
+
+void AstExpressionRewriter::VisitBinaryOperation(BinaryOperation* node) {
+  REWRITE_THIS(node);
+  AST_REWRITE_PROPERTY(Expression, node, left);
+  AST_REWRITE_PROPERTY(Expression, node, right);
+}
+
+
+void AstExpressionRewriter::VisitCompareOperation(CompareOperation* node) {
+  REWRITE_THIS(node);
+  AST_REWRITE_PROPERTY(Expression, node, left);
+  AST_REWRITE_PROPERTY(Expression, node, right);
+}
+
+
+void AstExpressionRewriter::VisitSpread(Spread* node) {
+  REWRITE_THIS(node);
+  AST_REWRITE_PROPERTY(Expression, node, expression);
+}
+
+
+void AstExpressionRewriter::VisitThisFunction(ThisFunction* node) {
+  REWRITE_THIS(node);
+  NOTHING();
+}
+
+
+void AstExpressionRewriter::VisitSuperPropertyReference(
+    SuperPropertyReference* node) {
+  REWRITE_THIS(node);
+  AST_REWRITE_PROPERTY(VariableProxy, node, this_var);
+  AST_REWRITE_PROPERTY(Expression, node, home_object);
+}
+
+
+void AstExpressionRewriter::VisitSuperCallReference(SuperCallReference* node) {
+  REWRITE_THIS(node);
+  AST_REWRITE_PROPERTY(VariableProxy, node, this_var);
+  AST_REWRITE_PROPERTY(VariableProxy, node, new_target_var);
+  AST_REWRITE_PROPERTY(VariableProxy, node, this_function_var);
+}
+
+
+void AstExpressionRewriter::VisitCaseClause(CaseClause* node) {
+  if (!node->is_default()) {
+    AST_REWRITE_PROPERTY(Expression, node, label);
+  }
+  VisitStatements(node->statements());
+}
+
+
+void AstExpressionRewriter::VisitEmptyParentheses(EmptyParentheses* node) {
+  NOTHING();
+}
+
+
+void AstExpressionRewriter::VisitDoExpression(DoExpression* node) {
+  REWRITE_THIS(node);
+  AST_REWRITE_PROPERTY(Block, node, block);
+  AST_REWRITE_PROPERTY(VariableProxy, node, result);
+}
+
+
+void AstExpressionRewriter::VisitRewritableAssignmentExpression(
+    RewritableAssignmentExpression* node) {
+  REWRITE_THIS(node);
+  AST_REWRITE_PROPERTY(Expression, node, expression);
+}
+
+
+}  // namespace internal
+}  // namespace v8