Feature/with statement js compiler (#439)

* Implements the step JS->FuzzIL for the With-Statement
* Implements two unit tests for the With-Statement

Author: TobiasWienand

Sources/Fuzzilli/Compiler/Compiler.swift

@@ -479,6 +479,13 @@ public class JavaScriptCompiler {
             let value = try compileExpression(throwStatement.argument)
             emit(ThrowException(), withInputs: [value])
 
+        case .withStatement(let withStatement):
+            let object = try compileExpression(withStatement.object)
+            emit(BeginWith(), withInputs: [object])
+            try enterNewScope {
+                try compileBody(withStatement.body)
+            }
+            emit(EndWith())
         }
     }
 

Sources/Fuzzilli/Compiler/Parser/parser.js

@@ -320,6 +320,12 @@ function parse(script, proto) {
             case 'ThrowStatement': {
                 return makeStatement('ThrowStatement', { argument: visitExpression(node.argument) });
             }
+            case 'WithStatement': {
+                let withStatement = {};
+                withStatement.object = visitExpression(node.object);
+                withStatement.body = visitStatement(node.body);
+                return makeStatement('WithStatement', withStatement);
+            }
             default: {
                 throw "Unhandled node type " + node.type;
             }

Sources/Fuzzilli/Protobuf/ast.pb.swift

@@ -875,6 +875,36 @@ public struct Compiler_Protobuf_ThrowStatement: @unchecked Sendable {
   fileprivate var _storage = _StorageClass.defaultInstance
 }
 
+public struct Compiler_Protobuf_WithStatement: @unchecked Sendable {
+  // SwiftProtobuf.Message conformance is added in an extension below. See the
+  // `Message` and `Message+*Additions` files in the SwiftProtobuf library for
+  // methods supported on all messages.
+
+  public var object: Compiler_Protobuf_Expression {
+    get {return _storage._object ?? Compiler_Protobuf_Expression()}
+    set {_uniqueStorage()._object = newValue}
+  }
+  /// Returns true if `object` has been explicitly set.
+  public var hasObject: Bool {return _storage._object != nil}
+  /// Clears the value of `object`. Subsequent reads from it will return its default value.
+  public mutating func clearObject() {_uniqueStorage()._object = nil}
+
+  public var body: Compiler_Protobuf_Statement {
+    get {return _storage._body ?? Compiler_Protobuf_Statement()}
+    set {_uniqueStorage()._body = newValue}
+  }
+  /// Returns true if `body` has been explicitly set.
+  public var hasBody: Bool {return _storage._body != nil}
+  /// Clears the value of `body`. Subsequent reads from it will return its default value.
+  public mutating func clearBody() {_uniqueStorage()._body = nil}
+
+  public var unknownFields = SwiftProtobuf.UnknownStorage()
+
+  public init() {}
+
+  fileprivate var _storage = _StorageClass.defaultInstance
+}
+
 public struct Compiler_Protobuf_Statement: @unchecked Sendable {
   // SwiftProtobuf.Message conformance is added in an extension below. See the
   // `Message` and `Message+*Additions` files in the SwiftProtobuf library for
@@ -1021,6 +1051,14 @@ public struct Compiler_Protobuf_Statement: @unchecked Sendable {
     set {_uniqueStorage()._statement = .throwStatement(newValue)}
   }
 
+  public var withStatement: Compiler_Protobuf_WithStatement {
+    get {
+      if case .withStatement(let v)? = _storage._statement {return v}
+      return Compiler_Protobuf_WithStatement()
+    }
+    set {_uniqueStorage()._statement = .withStatement(newValue)}
+  }
+
   public var unknownFields = SwiftProtobuf.UnknownStorage()
 
   public enum OneOf_Statement: Equatable, Sendable {
@@ -1041,6 +1079,7 @@ public struct Compiler_Protobuf_Statement: @unchecked Sendable {
     case continueStatement(Compiler_Protobuf_ContinueStatement)
     case tryStatement(Compiler_Protobuf_TryStatement)
     case throwStatement(Compiler_Protobuf_ThrowStatement)
+    case withStatement(Compiler_Protobuf_WithStatement)
 
   }
 
@@ -3896,6 +3935,90 @@ extension Compiler_Protobuf_ThrowStatement: SwiftProtobuf.Message, SwiftProtobuf
   }
 }
 
+extension Compiler_Protobuf_WithStatement: SwiftProtobuf.Message, SwiftProtobuf._MessageImplementationBase, SwiftProtobuf._ProtoNameProviding {
+  public static let protoMessageName: String = _protobuf_package + ".WithStatement"
+  public static let _protobuf_nameMap: SwiftProtobuf._NameMap = [
+    1: .same(proto: "object"),
+    2: .same(proto: "body"),
+  ]
+
+  fileprivate class _StorageClass {
+    var _object: Compiler_Protobuf_Expression? = nil
+    var _body: Compiler_Protobuf_Statement? = nil
+
+    #if swift(>=5.10)
+      // This property is used as the initial default value for new instances of the type.
+      // The type itself is protecting the reference to its storage via CoW semantics.
+      // This will force a copy to be made of this reference when the first mutation occurs;
+      // hence, it is safe to mark this as `nonisolated(unsafe)`.
+      static nonisolated(unsafe) let defaultInstance = _StorageClass()
+    #else
+      static let defaultInstance = _StorageClass()
+    #endif
+
+    private init() {}
+
+    init(copying source: _StorageClass) {
+      _object = source._object
+      _body = source._body
+    }
+  }
+
+  fileprivate mutating func _uniqueStorage() -> _StorageClass {
+    if !isKnownUniquelyReferenced(&_storage) {
+      _storage = _StorageClass(copying: _storage)
+    }
+    return _storage
+  }
+
+  public mutating func decodeMessage<D: SwiftProtobuf.Decoder>(decoder: inout D) throws {
+    _ = _uniqueStorage()
+    try withExtendedLifetime(_storage) { (_storage: _StorageClass) in
+      while let fieldNumber = try decoder.nextFieldNumber() {
+        // The use of inline closures is to circumvent an issue where the compiler
+        // allocates stack space for every case branch when no optimizations are
+        // enabled. https://github.com/apple/swift-protobuf/issues/1034
+        switch fieldNumber {
+        case 1: try { try decoder.decodeSingularMessageField(value: &_storage._object) }()
+        case 2: try { try decoder.decodeSingularMessageField(value: &_storage._body) }()
+        default: break
+        }
+      }
+    }
+  }
+
+  public func traverse<V: SwiftProtobuf.Visitor>(visitor: inout V) throws {
+    try withExtendedLifetime(_storage) { (_storage: _StorageClass) in
+      // The use of inline closures is to circumvent an issue where the compiler
+      // allocates stack space for every if/case branch local when no optimizations
+      // are enabled. https://github.com/apple/swift-protobuf/issues/1034 and
+      // https://github.com/apple/swift-protobuf/issues/1182
+      try { if let v = _storage._object {
+        try visitor.visitSingularMessageField(value: v, fieldNumber: 1)
+      } }()
+      try { if let v = _storage._body {
+        try visitor.visitSingularMessageField(value: v, fieldNumber: 2)
+      } }()
+    }
+    try unknownFields.traverse(visitor: &visitor)
+  }
+
+  public static func ==(lhs: Compiler_Protobuf_WithStatement, rhs: Compiler_Protobuf_WithStatement) -> Bool {
+    if lhs._storage !== rhs._storage {
+      let storagesAreEqual: Bool = withExtendedLifetime((lhs._storage, rhs._storage)) { (_args: (_StorageClass, _StorageClass)) in
+        let _storage = _args.0
+        let rhs_storage = _args.1
+        if _storage._object != rhs_storage._object {return false}
+        if _storage._body != rhs_storage._body {return false}
+        return true
+      }
+      if !storagesAreEqual {return false}
+    }
+    if lhs.unknownFields != rhs.unknownFields {return false}
+    return true
+  }
+}
+
 extension Compiler_Protobuf_Statement: SwiftProtobuf.Message, SwiftProtobuf._MessageImplementationBase, SwiftProtobuf._ProtoNameProviding {
   public static let protoMessageName: String = _protobuf_package + ".Statement"
   public static let _protobuf_nameMap: SwiftProtobuf._NameMap = [
@@ -3916,6 +4039,7 @@ extension Compiler_Protobuf_Statement: SwiftProtobuf.Message, SwiftProtobuf._Mes
     15: .same(proto: "continueStatement"),
     16: .same(proto: "tryStatement"),
     17: .same(proto: "throwStatement"),
+    18: .same(proto: "withStatement"),
   ]
 
   fileprivate class _StorageClass {
@@ -4174,6 +4298,19 @@ extension Compiler_Protobuf_Statement: SwiftProtobuf.Message, SwiftProtobuf._Mes
             _storage._statement = .throwStatement(v)
           }
         }()
+        case 18: try {
+          var v: Compiler_Protobuf_WithStatement?
+          var hadOneofValue = false
+          if let current = _storage._statement {
+            hadOneofValue = true
+            if case .withStatement(let m) = current {v = m}
+          }
+          try decoder.decodeSingularMessageField(value: &v)
+          if let v = v {
+            if hadOneofValue {try decoder.handleConflictingOneOf()}
+            _storage._statement = .withStatement(v)
+          }
+        }()
         default: break
         }
       }
@@ -4255,6 +4392,10 @@ extension Compiler_Protobuf_Statement: SwiftProtobuf.Message, SwiftProtobuf._Mes
         guard case .throwStatement(let v)? = _storage._statement else { preconditionFailure() }
         try visitor.visitSingularMessageField(value: v, fieldNumber: 17)
       }()
+      case .withStatement?: try {
+        guard case .withStatement(let v)? = _storage._statement else { preconditionFailure() }
+        try visitor.visitSingularMessageField(value: v, fieldNumber: 18)
+      }()
       case nil: break
       }
     }

Sources/Fuzzilli/Protobuf/ast.proto

@@ -202,6 +202,11 @@ message ThrowStatement {
     Expression argument = 1;
 }
 
+message WithStatement {
+    Expression object = 1;
+    Statement body = 2;
+}
+
 message Statement {
     oneof statement {
         EmptyStatement emptyStatement = 1;
@@ -221,6 +226,7 @@ message Statement {
         ContinueStatement continueStatement = 15;
         TryStatement tryStatement = 16;
         ThrowStatement throwStatement = 17;
+        WithStatement withStatement = 18;
     }
 }
 

Tests/FuzzilliTests/CompilerTests/basic_object_access.js

@@ -12,3 +12,11 @@ o[2] = o[1] + o[0];
 o[3] = o[2] + o[1];
 
 output(JSON.stringify(o));
+
+with(o) {
+    a = 3;
+    b = 4;
+    c = a + b;
+  }
+
+output(JSON.stringify(o));

Tests/FuzzilliTests/CompilerTests/basic_scoping.js

@@ -16,5 +16,12 @@ function foo(x) {
   }
   output(x);
   output(y);
+  let obj = { x: 45, y: 9001 };
+  with (obj) {
+    output(x);
+    output(y);
+  }
+  output(x);
+  output(y);
 }
 foo(44);