feature/forawaitof

Sources/Fuzzilli/Base/ProgramBuilder.swift

@@ -2748,6 +2748,19 @@ public class ProgramBuilder {
         emit(EndForLoop())
     }
 
+    public func buildForAwaitOfLoop(_ obj: Variable, _ body: (Variable) -> ()) {
+        let i = emit(BeginForAwaitOfLoop(), withInputs: [obj]).innerOutput
+        body(i)
+        emit(EndForAwaitOfLoop())
+    }
+
+    public func buildForAwaitOfLoop(_ obj: Variable, selecting indices: [Int64], hasRestElement: Bool = false, _ body: ([Variable]) -> ()) {
+        let instr = emit(BeginForAwaitOfLoopWithDestruct(indices: indices, hasRestElement: hasRestElement), withInputs: [obj])
+        body(Array(instr.innerOutputs))
+        emit(EndForAwaitOfLoop())
+    }
+
+
     public func buildForInLoop(_ obj: Variable, _ body: (Variable) -> ()) {
         let i = emit(BeginForInLoop(), withInputs: [obj]).innerOutput
         body(i)

Sources/Fuzzilli/CodeGen/CodeGeneratorWeights.swift

@@ -159,6 +159,8 @@ public let codeGeneratorWeights = [
     "DoWhileLoopGenerator":                     15,
     "SimpleForLoopGenerator":                   10,
     "ComplexForLoopGenerator":                  10,
+    "ForAwaitOfLoopGenerator":                  10,
+    "ForAwaitOfWithDestructLoopGenerator":      3,
     "ForInLoopGenerator":                       10,
     "ForOfLoopGenerator":                       10,
     "ForOfWithDestructLoopGenerator":           3,

Sources/Fuzzilli/CodeGen/CodeGenerators.swift

@@ -1420,6 +1420,33 @@ public let CodeGenerators: [CodeGenerator] = [
         }
     },
 
+    RecursiveCodeGenerator("ForAwaitOfLoopGenerator", inContext: .asyncFunction, inputs: .preferred(.iterable)) { b, obj in
+        assert(b.context.contains(.asyncFunction))
+
+        b.buildForAwaitOfLoop(obj) { _ in
+            b.buildRecursive()
+        }
+    },
+
+    RecursiveCodeGenerator("ForAwaitOfWithDestructLoopGenerator", inContext: .asyncFunction, inputs: .preferred(.iterable)) { b, obj in
+        assert(b.context.contains(.asyncFunction))
+
+        var indices: [Int64] = []
+        for idx in 0..<Int64.random(in: 1..<5) {
+            withProbability(0.8) {
+                indices.append(idx)
+            }
+        }
+
+        if indices.isEmpty {
+            indices = [0]
+        }
+
+        b.buildForOfLoop(obj, selecting: indices, hasRestElement: probability(0.2)) { _ in
+            b.buildRecursive()
+        }
+    },
+
     RecursiveCodeGenerator("ForInLoopGenerator", inputs: .preferred(.object())) { b, obj in
         b.buildForInLoop(obj) { _ in
             b.buildRecursive()

Sources/Fuzzilli/Compiler/Compiler.swift

@@ -416,6 +416,27 @@ public class JavaScriptCompiler {
 
             emit(EndForLoop())
 
+        case .forAwaitOfLoop(let forAwaitOfLoop):
+            let initializer = forAwaitOfLoop.left;
+
+            if !contextAnalyzer.context.contains(.asyncFunction) {
+                    throw CompilerError.invalidNodeError("`for await...of` is currently only supported in async functions")
+            }
+
+            guard !initializer.hasValue else {
+                throw CompilerError.invalidNodeError("Expected no initial value for the variable declared in a for-await-of loop")
+            }
+
+            let obj = try compileExpression(forAwaitOfLoop.right)
+
+            let loopVar = emit(BeginForAwaitOfLoop(), withInputs: [obj]).innerOutput
+            try enterNewScope {
+                map(initializer.name, to: loopVar)
+                try compileBody(forAwaitOfLoop.body)
+            }
+
+            emit(EndForAwaitOfLoop())
+
         case .forInLoop(let forInLoop):
             let initializer = forInLoop.left;
             guard !initializer.hasValue else {

Sources/Fuzzilli/Compiler/Parser/parser.js

@@ -281,6 +281,18 @@ function parse(script, proto) {
                 forLoop.body = visitStatement(node.body);
                 return makeStatement('ForLoop', forLoop);
             }
+            case 'ForAwaitOfStatement': {
+                assert(node.left.type === 'VaraibleDeclaration', "Expected variable declaration as init part of a for-await-of loop, found " + node.left.type)
+                assert(node.left.declarations.length === 1, "Expected exactly one variable declaration in the init part of a for-await-of loop");
+                let decl = node.left.declarations[0];
+                let forAwaitOfLoop = {};
+                let initDecl = { name: decl.id.name };
+                assert(decl.init == null, "Expected no initial value for the varaible declared as part of a for-await-of loop")
+                forAwaitOfLoop.left = make('VariableDeclarator', initDecl);
+                forAwaitOfLoop.right = visitExpression(node.right);
+                forAwaitOfLoop.body = visitStatement(node.body);
+                return makeStatement('ForAwaitOfLoop', forAwaitOfLoop);
+            }
             case 'ForInStatement': {
                 assert(node.left.type === 'VariableDeclaration', "Expected variable declaration as init part of a for-in loop, found " + node.left.type);
                 assert(node.left.declarations.length === 1, "Expected exactly one variable declaration in the init part of a for-in loop");
@@ -294,12 +306,12 @@ function parse(script, proto) {
                 return makeStatement('ForInLoop', forInLoop);
             }
             case 'ForOfStatement': {
-                assert(node.left.type === 'VariableDeclaration', "Expected variable declaration as init part of a for-in loop, found " + node.left.type);
-                assert(node.left.declarations.length === 1, "Expected exactly one variable declaration in the init part of a for-in loop");
+                assert(node.left.type === 'VariableDeclaration', "Expected variable declaration as init part of a for-of loop, found " + node.left.type);
+                assert(node.left.declarations.length === 1, "Expected exactly one variable declaration in the init part of a for-of loop");
                 let decl = node.left.declarations[0];
                 let forOfLoop = {};
                 let initDecl = { name: decl.id.name };
-                assert(decl.init == null, "Expected no initial value for the variable declared as part of a for-in loop")
+                assert(decl.init == null, "Expected no initial value for the variable declared as part of a for-of loop")
                 forOfLoop.left = make('VariableDeclarator', initDecl);
                 forOfLoop.right = visitExpression(node.right);
                 forOfLoop.body = visitStatement(node.body);

Sources/Fuzzilli/FuzzIL/Instruction.swift

@@ -948,6 +948,15 @@ extension Instruction: ProtobufConvertible {
                 $0.beginForLoopBody = Fuzzilli_Protobuf_BeginForLoopBody()
             case .endForLoop:
                 $0.endForLoop = Fuzzilli_Protobuf_EndForLoop()
+            case .beginForAwaitOfLoop:
+                $0.beginForAwaitOfLoop = Fuzzilli_Protobuf_BeginForAwaitOfLoop()
+            case .beginForAwaitOfLoopWithDestruct(let op):
+                $0.beginForAwaitOfLoopWithDestruct = Fuzzilli_Protobuf_BeginForAwaitOfLoopWithDestruct.with {
+                    $0.indices = op.indices.map({ Int32($0) })
+                    $0.hasRestElement_p = op.hasRestElement
+                }
+            case .endForAwaitOfLoop:
+                $0.endForAwaitOfLoop = Fuzzilli_Protobuf_EndForAwaitOfLoop()
             case .beginForInLoop:
                 $0.beginForInLoop = Fuzzilli_Protobuf_BeginForInLoop()
             case .endForInLoop:
@@ -1852,6 +1861,12 @@ extension Instruction: ProtobufConvertible {
             op = BeginForLoopBody(numLoopVariables: inouts.count)
         case .endForLoop:
             op = EndForLoop()
+        case .beginForAwaitOfLoop:
+            op = BeginForAwaitOfLoop()
+        case .beginForAwaitOfLoopWithDestruct(let p):
+            op = BeginForAwaitOfLoopWithDestruct(indices: p.indices.map({ Int64($0) }), hasRestElement: p.hasRestElement_p)
+        case .endForAwaitOfLoop:
+            op = EndForAwaitOfLoop()
         case .beginForInLoop:
             op = BeginForInLoop()
         case .endForInLoop:

Sources/Fuzzilli/FuzzIL/JSTyper.swift

@@ -398,6 +398,8 @@ public struct JSTyper: Analyzer {
         case .endForLoop:
             state.endGroupOfConditionallyExecutingBlocks(typeChanges: &typeChanges)
         case .beginWhileLoopBody,
+             .beginForAwaitOfLoop,
+             .beginForAwaitOfLoopWithDestruct,
              .beginForInLoop,
              .beginForOfLoop,
              .beginForOfLoopWithDestruct,
@@ -409,6 +411,7 @@ public struct JSTyper: Analyzer {
             // Push a new state tracking the types inside the loop
             state.enterConditionallyExecutingBlock(typeChanges: &typeChanges)
         case .endWhileLoop,
+             .endForAwaitOfLoop,
              .endForInLoop,
              .endForOfLoop,
              .endRepeatLoop,
@@ -926,6 +929,14 @@ public struct JSTyper: Analyzer {
             assert(inputTypes.count == instr.numInnerOutputs)
             zip(instr.innerOutputs, inputTypes).forEach({ set($0, $1) })
 
+        case .beginForAwaitOfLoop:
+            set(instr.innerOutput, .string)
+
+        case .beginForAwaitOfLoopWithDestruct:
+            for v in instr.innerOutputs {
+                set(v, .anything)
+            }
+
         case .beginForInLoop:
             set(instr.innerOutput, .string)
 

Sources/Fuzzilli/FuzzIL/JsOperations.swift

@@ -2140,6 +2140,37 @@ final class EndForLoop: JsOperation {
     }
 }
 
+final class BeginForAwaitOfLoop: JsOperation {
+    override var opcode: Opcode { .beginForAwaitOfLoop(self) }
+
+    init() {
+        super.init(numInputs: 1, numInnerOutputs: 1, attributes: [.isBlockStart, .propagatesSurroundingContext], contextOpened: [.javascript, .loop, .asyncFunction])
+    }
+}
+
+final class BeginForAwaitOfLoopWithDestruct: JsOperation {
+    override var opcode: Opcode { .beginForAwaitOfLoopWithDestruct(self) }
+
+    let indices: [Int64]
+    let hasRestElement: Bool
+
+    init(indices: [Int64], hasRestElement: Bool) {
+        assert(indices.count >= 1)
+        self.indices = indices
+        self.hasRestElement = hasRestElement
+        super.init(numInputs: 1, numInnerOutputs: indices.count, attributes: [.isBlockStart, .propagatesSurroundingContext], contextOpened: [.javascript, .loop, .asyncFunction])
+    }  
+}
+
+final class EndForAwaitOfLoop: JsOperation {
+    override var opcode: Opcode { .endForAwaitOfLoop(self) }
+
+    init() {
+        super.init(attributes: .isBlockEnd)
+    }
+}
+
+
 final class BeginForInLoop: JsOperation {
     override var opcode: Opcode { .beginForInLoop(self) }
 

Sources/Fuzzilli/FuzzIL/Opcodes.swift

@@ -177,6 +177,9 @@ enum Opcode {
     case beginForLoopAfterthought(BeginForLoopAfterthought)
     case beginForLoopBody(BeginForLoopBody)
     case endForLoop(EndForLoop)
+    case beginForAwaitOfLoop(BeginForAwaitOfLoop)
+    case beginForAwaitOfLoopWithDestruct(BeginForAwaitOfLoopWithDestruct)
+    case endForAwaitOfLoop(EndForAwaitOfLoop)
     case beginForInLoop(BeginForInLoop)
     case endForInLoop(EndForInLoop)
     case beginForOfLoop(BeginForOfLoop)

Sources/Fuzzilli/FuzzIL/Semantics.swift

@@ -203,6 +203,9 @@ extension Operation {
             return endOp is BeginForLoopBody
         case .beginForLoopBody:
             return endOp is EndForLoop
+        case .beginForAwaitOfLoop,
+             .beginForAwaitOfLoopWithDestruct:
+            return endOp is EndForAwaitOfLoop
         case .beginForInLoop:
             return endOp is EndForInLoop
         case .beginForOfLoop,

Sources/Fuzzilli/Lifting/FuzzILLifter.swift

@@ -673,6 +673,19 @@ public class FuzzILLifter: Lifter {
             w.decreaseIndentionLevel()
             w.emit("EndForLoop")
 
+        case .beginForAwaitOfLoop:
+            w.emit("BeginForAwaitOfLooop \(input(0)) -> \(innerOutput())")
+            w.increaseIndentionLevel()
+
+        case .beginForAwaitOfLoopWithDestruct(let op):
+            let outputs = instr.innerOutputs.map(lift)
+            w.emit("BeginForAwaitOfLoopWithDestruct \(input(0)) -> [\(liftArrayDestructPattern(indices: op.indices, outputs: outputs, hasRestElement: op.hasRestElement))]")
+            w.increaseIndentionLevel()
+
+        case .endForAwaitOfLoop:
+            w.decreaseIndentionLevel()
+            w.emit("EndForAwaitOfLoop")
+
         case .beginForInLoop:
             w.emit("BeginForInLoop \(input(0)) -> \(innerOutput())")
             w.increaseIndentionLevel()

Sources/Fuzzilli/Lifting/JavaScriptLifter.swift

@@ -1263,6 +1263,25 @@ public class JavaScriptLifter: Lifter {
                 w.leaveCurrentBlock()
                 w.emit("}")
 
+            case .beginForAwaitOfLoop:
+                let V = w.declare(instr.innerOutput)
+                let LET = w.declarationKeyword(for: instr.innerOutput)
+                let OBJ = input(0)
+                w.emit("for await (\(LET) \(V) of \(OBJ)) {")
+                w.enterNewBlock()
+
+            case .beginForAwaitOfLoopWithDestruct(let op):
+                let outputs = w.declareAll(instr.innerOutputs)
+                let PATTERN = liftArrayDestructPattern(indices: op.indices, outputs: outputs, hasRestElement: op.hasRestElement)
+                let LET = w.varKeyword
+                let OBJ = input(0)
+                w.emit("for await (\(LET) [\(PATTERN)] of \(OBJ)) {")
+                w.enterNewBlock()
+
+            case .endForAwaitOfLoop:
+                w.leaveCurrentBlock()
+                w.emit("}")
+
             case .beginForInLoop:
                 let LET = w.declarationKeyword(for: instr.innerOutput)
                 let V = w.declare(instr.innerOutput)

Sources/Fuzzilli/Minimization/BlockReducer.swift

@@ -51,6 +51,8 @@ struct BlockReducer: Reducer {
             case .beginWhileLoopHeader,
                  .beginDoWhileLoopBody,
                  .beginForLoopInitializer,
+                 .beginForAwaitOfLoop,
+                 .beginForAwaitOfLoopWithDestruct,
                  .beginForInLoop,
                  .beginForOfLoop,
                  .beginForOfLoopWithDestruct,

Sources/Fuzzilli/Minimization/LoopSimplifier.swift

@@ -40,9 +40,11 @@ struct LoopSimplifier: Reducer {
                 tryReplaceDoWhileLoopWithRepeatLoop(group, with: helper)
             case .beginRepeatLoop:
                 tryReduceRepeatLoopIterationCount(group, with: helper)
-            case .beginForInLoop,
-                    .beginForOfLoop,
-                    .beginForOfLoopWithDestruct:
+            case .beginForAwaitOfLoop,
+                 .beginForAwaitOfLoopWithDestruct,
+                 .beginForInLoop,
+                 .beginForOfLoop,
+                 .beginForOfLoopWithDestruct:
                 // These loops are (usually) guaranteed to terminate, and should probably anyway not be replaced by repeat-loops.
                 break
             default:

Sources/Fuzzilli/Mutators/OperationMutator.swift

@@ -478,6 +478,9 @@ public class OperationMutator: BaseInstructionMutator {
              .beginForLoopAfterthought(_),
              .beginForLoopBody(_),
              .endForLoop(_),
+             .beginForAwaitOfLoop(_),
+             .beginForAwaitOfLoopWithDestruct(_),
+             .endForAwaitOfLoop(_),
              .beginForInLoop(_),
              .endForInLoop(_),
              .beginForOfLoop(_),