Unable to remove types metadata and methods names from compiled binary

Using Swift
,
1

Hi. I'm trying to compile simple swift source file with stripping types metadata and names from it. I use these frontend flags:

swiftc -O -Xfrontend -disable-reflection-names -Xfrontend -disable-reflection-metadata -Xfrontend -reflection-metadata-for-debugger-only -Xfrontend -disable-generic-metadata-prespecialization -gnone test.swift

After compiling this test source file I still facing metadata and names in binary after dissembling it with Hopper. What I'm doing wrong? Please help.

For example, my code looks like this:

protocol Logger {

  func log()

}

struct CoreLogger: Logger {

  func log() {
    print("CoreLogger log")
  }

}

struct LogManager {

  private let logger: Logger

  init(logger: Logger) {
    self.logger = logger
  }

  func run() {
    logger.log()
  }

}

let logger = CoreLogger()
let logManager = LogManager(logger: logger)
logManager.run()
1 Like
2

My guess that this behavior was changed 2+ years ago to make SwiftUI work as it uses View's name to identify AttributeGraph nodes. Previously disabling reflection metadata caused immediate crash for apps using SwiftUI, seems like they 'fixed' it this way.

3

since this has been resurrected, you may find this more recent discussion on metadata removal of interest: Why nominal type descriptors are always marked 'no dead strip'?

in particular, if you add the flags -Xfrontend -conditional-runtime-records -lto=llvm-thin to the compiler invocation in the example, i think you'll find that more metadata is removed. i will, however, reiterate these caveats from that discussion: