Feature/ternary expression js compiler (#438)

* Makes conditional expressions compilable from JS to FuzzIL
* Implements unit test for tertiary expression compilation

Sources/Fuzzilli/Compiler/Compiler.swift

@@ -505,6 +505,13 @@ public class JavaScriptCompiler {
 
         switch expr {
 
+        case .ternaryExpression(let ternaryExpression):
+            let condition = try compileExpression(ternaryExpression.condition)
+            let consequent = try compileExpression(ternaryExpression.consequent)
+            let alternate = try compileExpression(ternaryExpression.alternate)
+            return emit(TernaryOperation(), withInputs: [condition, consequent, alternate]).output
+
+
         case .identifier(let identifier):
             // Identifiers can generally turn into one of three things:
             //  1. A FuzzIL variable that has previously been associated with the identifier

Sources/Fuzzilli/Compiler/Parser/parser.js

@@ -34,8 +34,8 @@ function tryReadFile(path) {
 
 // Parse the given JavaScript script and return an AST compatible with Fuzzilli's protobuf-based AST format.
 function parse(script, proto) {
-    let ast = Parser.parse(script, { plugins: ["v8intrinsic"] });
-
+    let ast = Parser.parse(script, { plugins: ["v8intrinsic"] }); 
+    
     function assertNoError(err) {
         if (err) throw err;
     }
@@ -519,6 +519,12 @@ function parse(script, proto) {
                 let argument = visitExpression(node.argument);
                 return makeExpression('UnaryExpression', { operator, argument });
             }
+            case 'ConditionalExpression': {
+                let condition = visitExpression(node.test);
+                let consequent = visitExpression(node.consequent);
+                let alternate = visitExpression(node.alternate);
+                return makeExpression('TernaryExpression', { condition, consequent, alternate });
+            }
             case 'BinaryExpression':
             case 'LogicalExpression': {
                 let operator = node.operator;
@@ -571,7 +577,7 @@ protobuf.load(astProtobufDefinitionPath, function(err, root) {
 
     // Uncomment this to print the AST to stdout (will be very verbose).
     //console.log(JSON.stringify(ast, null, 2));
-
+    
     const AST = root.lookupType('compiler.protobuf.AST');
     let buffer = AST.encode(ast).finish();