Enable the FuzzIL compiler to directly output a JS file

This will be used by an automated script compiling and lifting
test cases from e.g. test262.

Bug: 442444727
Change-Id: I0b2321e44e0def292cd88a103a46b03960ee1d55
Reviewed-on: https://chrome-internal-review.googlesource.com/c/v8/fuzzilli/+/8680076
Commit-Queue: Michael Achenbach <[email protected]>
Reviewed-by: Matthias Liedtke <[email protected]>

Author: mi-ac

Sources/FuzzILTool/main.swift

@@ -95,7 +95,7 @@ func loadProgramOrExit(from path: String) -> Program {
 
 let args = Arguments.parse(from: CommandLine.arguments)
 
-if args["-h"] != nil || args["--help"] != nil || args.numPositionalArguments != 1 || args.numOptionalArguments > 2 {
+if args["-h"] != nil || args["--help"] != nil || args.numPositionalArguments != 1 {
     print("""
           Usage:
           \(args.programName) options path
@@ -108,6 +108,7 @@ if args["-h"] != nil || args["--help"] != nil || args.numPositionalArguments !=
               --dumpProgram            : Dumps the internal representation of the program stored in the given protobuf file
               --checkCorpus            : Attempts to load all .fzil files in a directory and checks if they are statically valid
               --compile                : Compile the given JavaScript program to a FuzzIL program. Requires node.js
+              --outputPathJS           : If given, --compile will write the lifted JS file to the given path after compilation.
               --generate               : Generate a random program using Fuzzilli's code generators and save it to the specified path.
               --forDifferentialFuzzing : Enable additional features for better support of external differential fuzzing.
           """)
@@ -186,17 +187,27 @@ else if args.has("--compile") {
         exit(-1)
     }
 
-    print(fuzzILLifter.lift(program))
-    print()
-    print(jsLifter.lift(program))
+    if let js_path = args["--outputPathJS"] {
+        let content = jsLifter.lift(program)
+        do {
+            try content.write(to: URL(fileURLWithPath: js_path), atomically: false, encoding: String.Encoding.utf8)
+        } catch {
+            print("Failed to write file \(js_path): \(error)")
+            exit(-1)
+        }
+    } else {
+        print(fuzzILLifter.lift(program))
+        print()
+        print(jsLifter.lift(program))
 
-    do {
-        let outputPath = URL(fileURLWithPath: path).deletingPathExtension().appendingPathExtension("fzil")
-        try program.asProtobuf().serializedData().write(to: outputPath)
-        print("FuzzIL program written to \(outputPath.relativePath)")
-    } catch {
-        print("Failed to store output program to disk: \(error)")
-        exit(-1)
+        do {
+            let outputPath = URL(fileURLWithPath: path).deletingPathExtension().appendingPathExtension("fzil")
+            try program.asProtobuf().serializedData().write(to: outputPath)
+            print("FuzzIL program written to \(outputPath.relativePath)")
+        } catch {
+            print("Failed to store output program to disk: \(error)")
+            exit(-1)
+        }
     }
 }